Textbook of Urgent Care Medicine, Chapter 43, Common Dermatologic Conditions

Original authors: Margot P. Shuman and Toni Clare Hogencamp

Originally published in 2014. Substantially updated and clinically reviewed in 2026.

This edition updates diagnosis, treatment, infection control, and transfer decisions while retaining the chapter's pattern-recognition and clinical-pearls approach. Recommendations for specialty or inpatient therapy are provided to explain referral rather than to suggest that urgent care centers can deliver those treatments.

INTRODUCTION

A majority of disorders present with some type of cutaneous physical findings; an understanding of how to interpret these findings is key to diagnosing and treating underlying disorders. Dermatologic complaints are particularly common in the pediatric population.

It is essential for the urgent care practitioner to have the skills necessary to distinguish between those findings that represent serious illness requiring immediate treatment and those that can be treated symptomatically or expectantly with referral back to the primary care provider for further evaluation and treatment.

PRESENTATION

Many acute infections present with primary skin findings, but a large percentage of dermatologic complaints are manifestations of other underlying illness, subacute or chronic infection, or secondary immunologic responses.

Differential diagnosis of presenting skin rashes ranges from life-threatening to chronic self-limited conditions.

First decide whether the patient is ill appearing, febrile, hypotensive, hypoxic, immunocompromised, or experiencing rapidly progressive rash, severe pain, blistering, mucosal disease, or purpura. These features may signify a condition that cannot be evaluated safely with routine outpatient dermatologic testing.

HISTORY PEARLS

All dermatologic symptoms must be interpreted in the context of a patient's unique medical history and current illness. The same findings can result from entirely different diagnoses in patients of different ages, medical histories, and backgrounds as follows:

Demographic Characteristics

• Age
• Ethnicity

Describe the skin findings on the patient's observed skin tone; erythema may appear violaceous, gray, or subtle rather than bright red in darker skin. Skin of color and background pigmentation affect appearance without independently establishing etiology.

Timing

• Onset and duration
• Chronicity and recurrence: Continuous, intermittent, or cyclic

Triggers

• Environmental allergens or irritants
• Animals or insects
• Foods or medications
• Infection or illness

Record newly started medications, including antibiotics, anticonvulsants, allopurinol, nonprescription products, and recent dose changes. A new medication coupled with fever, skin pain, or mucosal lesions raises concern for a severe cutaneous adverse reaction.

Past Medical History

• Birth and prenatal: Maternal illness, delivery trauma, neonatal course
• Nutrition and medications
• Preexisting conditions and chronic illness
• Exposures: Travel and social contacts

Include vaccination status, immune suppression, sick contacts, recent tick exposure, pregnancy, and recent hospitalizations when relevant.

Family History

• Infectious disease
• Immunology
• Rheumatology

Review of Systems: Concomitant and Recent Symptoms

• Constitutional: Fever, fatigue, oral intake
• Head, ears, eyes, nose, and throat: Rhinitis or rhinorrhea, pharyngitis, conjunctivitis
• Cardiovascular or pulmonary: Cough, shortness of breath, wheezing, chest pain
• Gastrointestinal: Abdominal pain, nausea or vomiting, diarrhea, blood in the stool
• Genitourinary: Dysuria, hematuria
• Musculoskeletal: Arthralgia or arthritis, limp
• Hematologic: Jaundice, lymphadenopathy
• Neurologic: Headache, impaired vision, weakness, irritability

PHYSICAL EXAM PEARLS

Pattern recognition is key to visual diagnosis of dermatologic findings. Photography is often a useful tool in dermatologic evaluation.

Detailed description will often allow a practitioner to correctly categorize the findings and accurately discuss findings with other specialists if needed.

Obtain consent for clinical photography and follow privacy procedures. Document lesion dimensions, morphology, distribution, tenderness, blanching, and whether mucosal surfaces are involved. A full examination is preferable to diagnosing an isolated photograph when severe disease is possible.

Morphology

• Macular: Flat patches <1 cm in diameter
• Papular: Small raised lesions only up to several millimeters in diameter
• Plaque: Superficial raised "flat-topped" lesion >0.5 cm in diameter
• Nodule: Raised "round-topped" lesion
• Vesicular: Small blisters
• Bullous: Large blisters
• Annular: Ringlike
• Polymorphous

Appearance of Individual Lesions

• Blanching
• Ecchymosis: >1 cm, nonblanching, "purple"
• Petechial: <0.3 cm, nonblanching, bright red
• Purpura: 0.3-1 cm, nonblanching, "purple"
• Color: Pink to red, black, blue, yellow, brown, or variegated
• Texture: Smooth, scaly, desquamative, lichenified, crusting, oozing

Distribution, Location, and Progression

• Central
• Acral
• Extensor or flexor
• Intertriginous
• "Glove and stocking"
• Palms and soles
• Mucosal
• Photo-exposed areas
• Generalized
• Radiation: Cephalocaudal, centrifugal, centripetal
• Evanescent: Short-lived or "waxing and waning"

DIAGNOSIS AND TREATMENT PEARLS

Petechial and Purpuric Rashes

Petechial, purpuric, and ecchymotic rashes result from alterations in vascular permeability, platelet function abnormalities, platelet number abnormalities, or other coagulopathies.

Nonblanching rash with fever, toxic appearance, hypotension, rapidly spreading lesions, or altered mental status is an emergency. Do not delay EMS transfer or receiving-hospital resuscitation to complete outpatient laboratory testing. A normal early platelet count does not exclude meningococcemia or another evolving infection. [1]

Meningococcemia, Purpura Fulminans, and Septic Coagulopathy

Neisseria meningitidis is a Gram-negative diplococcus.

These rashes also result from other infectious agents.

Diffuse, polymorphic petechiae and purpura.

Meningococcal septicemia may progress within hours, sometimes before classic meningeal findings appear. Immediately activate EMS for suspected invasive disease, use appropriate infection precautions, and notify the receiving hospital. Ceftriaxone or cefotaxime is a hospital-level empiric treatment; antibiotic administration should not be delayed once sepsis is recognized by appropriately equipped clinicians. [1]

Rocky Mountain Spotted Fever

Tick-borne illness: Causative organism is Rickettsia rickettsii.

Flu-like illness with malaise, headache.

Early RMSF may have no rash, and the rash is not always petechial or confined to wrists and ankles. Clinical suspicion depends on compatible illness and exposure; laboratory confirmation is often negative early. [2]

Begin doxycycline promptly when RMSF is suspected, including in children younger than 8 years. Adults receive 100 mg orally every 12 hours; children weighing less than 45 kg receive 2.2 mg/kg every 12 hours (maximum 100 mg per dose). Treat for a minimum of 5–7 days and at least 3 days after fever resolves, with individualized care. Severe illness requires emergency department evaluation and often hospitalization. [2]

Other Infections Presenting With Petechiae

Viral illnesses (e.g., echovirus).

Group A beta-hemolytic Streptococcus (GABHS) (Streptococcus pyogenes).

Distinguish an otherwise well child with localized petechiae after coughing or vomiting from a febrile or ill patient with diffuse nonblanching lesions. Distribution and appearance alone cannot reliably exclude invasive infection; assess vital signs, overall appearance, perfusion, and progression before deciding on outpatient care.

IgA Vasculitis (Previously Henoch-Schönlein Purpura)

Systemic vasculitis: Immunoglobulin A (IgA)-mediated small vessel disease.

Dependent purpura is most commonly seen on the buttocks and lower extremities.

Joint pain and swelling, typically of the ankle, knee, or hip.

Obtain blood pressure and urinalysis to screen for kidney involvement at diagnosis, and arrange repeat blood pressure and urinalysis follow-up for at least 6 months, with longer nephrology-directed monitoring if nephritis occurs. Abdominal pain, gastrointestinal bleeding, testicular symptoms, hypertension, or kidney abnormalities require urgent further assessment. Corticosteroids are not recommended solely to prevent nephritis. [3]

Immune Thrombocytopenia (ITP)

Antibody-mediated platelet destruction.

Patients are typically well-appearing without other systemic symptoms.

Isolated petechiae, easy bruising, or mucosal bleeding may accompany thrombocytopenia. Obtain a CBC when clinically indicated and assess for significant bleeding; severe hemorrhage, neurologic symptoms, or marked thrombocytopenia warrants emergency hematology evaluation. Treatment decisions depend on bleeding severity and specialist guidance, not platelet count alone.

Thrombocytopenia Secondary to Other Processes

Bone marrow infiltration by leukemia cells.

Abnormal platelet production or function.

Platelet sequestration (e.g., portal hypertension, hypersplenism, large hemangioma).

Consider leukemia, marrow failure, medication toxicity, disseminated infection, and systemic coagulopathy in patients with concerning constitutional symptoms, hepatosplenomegaly, or abnormalities in more than one blood cell line. Arrange emergency evaluation when the patient is ill or bleeding.

Trauma

Direct injury to underlying vasculature.

Possible petechiae, purpura, or ecchymosis at the site of direct injury.

Bruising patterns inconsistent with the account, patterned marks, bruises in nonmobile infants, or injuries in protected areas require a structured safeguarding assessment and documentation. Avoid assuming that a particular skin pattern alone proves or excludes abuse; follow reporting requirements and use pediatric child-protection resources when indicated.

Petechiae and Purpura in Other Systemic or Congenital Diseases

Alterations in vascular permeability.

Platelet abnormalities (number and function).

Malignancies.

Consider connective tissue disorders, inherited bleeding disorders, liver disease, and medication effects according to the history and examination. Unexplained recurrent purpura, mucosal bleeding, or associated anemia requires appropriate diagnostic workup and follow-up.

Papules, Plaques, and Pruritus

Papular and pruritic skin lesions are extremely common; the initial differential diagnosis includes acquired or hypersensitivity dermatitides, primary infection, and infestation etiologies.

In otherwise stable patients, treatment is directed at the cause and symptom relief. Fever with rapidly spreading erythema, skin pain, mucosal lesions, or systemic toxicity changes the disposition substantially.

Contact Dermatitis

Acquired inflammatory skin reaction.

Allergy or exposure to physical, mechanical, or chemical irritation.

Erythema, scaling, lichenification, xerosis, or cracking with chronic exposures.

Distinguish irritant from allergic contact dermatitis by the exposure history and distribution. Avoid the offending agent, provide bland emollients, and consider a short course of appropriately potent topical corticosteroid for inflamed areas. For extensive severe allergic reactions (including rhus dermatitis), an oral corticosteroid taper may be needed after checking contraindications; a very brief course can cause rebound. Refer persistent or recurrent disease for patch testing. [4]

Photodermatitis ("Sun Poisoning")

Hypersensitivity reaction secondary to sunlight.

Patches of erythematous pruritic rash in photo-exposed areas.

Review medications and products that can trigger phototoxic or photoallergic reactions (including some antibiotics, NSAIDs, and fragrances). Recommend sun avoidance, protective clothing, cool compresses, emollients, and appropriately selected topical corticosteroids. Refer blistering, large-area burns, severe pain, dehydration, or diagnostic uncertainty.

Atopic Dermatitis

Chronic inflammatory condition with genetic predisposition.

Environmental allergies and sensitivities.

Pustular lesions suggest superinfection with Staphylococcus aureus.

Regular emollients and appropriately selected topical corticosteroids remain foundational treatment. Topical calcineurin inhibitors and newer nonsteroidal agents can be considered for suitable patients; avoid routine systemic corticosteroids and routine topical antimicrobials in uncomplicated eczema. Recurrent, widespread, or treatment-resistant disease merits dermatology follow-up. [5]

Eczema herpeticum presents with painful, monomorphic erosions or punched-out lesions and may require urgent systemic antiviral therapy; ocular symptoms or extensive involvement warrant emergency assessment.

Psoriasis

Complex immune-mediated disease with genetic predisposition.

Plaque psoriasis: Silver-scaled plaques on extensor surfaces.

Guttate psoriasis: Multiple small guttate lesions ("raindrops").

Mild localized plaque disease may be managed initially with emollients and topical corticosteroids, with steroid-sparing agents such as vitamin D analogs when appropriate. Scalp, nail, intertriginous, widespread, or function-limiting disease benefits from dermatology evaluation; fever with diffuse erythema, generalized pustules, or systemic illness requires urgent assessment. [6]

Pityriasis Rosea

"Herald patch": A single 2- to 5-cm oval, circumscribed lesion, erythematous and blanching, with a collarette of scale and central clearing.

"Christmas tree" distribution.

This eruption is generally self-limited. Provide reassurance and symptomatic relief for pruritus. Consider secondary syphilis, tinea, medication eruptions, and atypical viral rashes when the presentation is unusual, involves palms and soles, or persists beyond the expected course. Pregnancy merits additional evaluation when the diagnosis is uncertain.

Folliculitis

Clusters of inflamed pustules or papules at and around hair follicles, typically in a confined area of distribution.

Associated pruritus.

Mild superficial folliculitis usually responds to hygiene, avoidance of friction or shaving, and warm compresses; antiseptic washes or topical antibiotics may be appropriate for select bacterial presentations. Culture recurrent, widespread, or treatment-refractory infection when feasible. Evaluate abscess, fever, spreading cellulitis, or hot-tub-associated symptoms separately. [7]

Common Verrucae (Warts)

Human papillomaviruses.

Most commonly occur in children and young adults.

Observe asymptomatic warts when acceptable. Salicylic acid and clinician-performed cryotherapy are common first-line options; avoid damaging surrounding healthy skin, particularly on digits. Refractory, atypical, painful, genital, or rapidly changing lesions warrant further evaluation. [8]

Molluscum Contagiosum

Molluscum contagiosum virus, a member of the poxvirus family.

Umbilicated papules: Flesh-colored, dome-shaped firm papules, 2 to 5 mm in diameter, with a shiny surface and often with central indentation.

Reassurance and watchful waiting are reasonable for uncomplicated lesions. When treatment is desired, clinician-applied cantharidin 0.7% is FDA-approved for patients aged 2 years and older, and topical berdazimer is FDA-approved for patients aged 1 year and older. Choice of treatment depends on lesion location, patient age, burden, tolerability, and availability. [9], [24]

Gianotti-Crosti Syndrome (Papular Acrodermatitis of Childhood)

Symmetric eruption of monomorphous pink-brown papules and papulovesicles with acral distribution to cheeks, buttocks, and extensor surfaces of extremities; no mucosal involvement.

Most cases are self-limited and need only skin care and pruritus relief. Investigate or refer when there is jaundice, hepatomegaly, prolonged systemic illness, or other evidence of underlying infection; routine extensive laboratory testing is not necessary for an otherwise well child with a typical eruption.

Infestations and Insects

Head Lice

Pediculus humanus capitis: A parasitic insect Pediculus humanus capitis that feeds on human blood.

Pruritus of the scalp around the ears is most common.

Confirm active infestation by identifying a live crawling louse; nits alone, particularly distant from the scalp, do not establish active infection. Use an age-appropriate pediculicide according to its instructions. Permethrin 1% may be used in eligible patients, but resistance occurs; a repeat application at approximately day 9 may be required. Consider prescription alternatives after documented treatment failure and inspect household contacts. [10]

Bedbugs

Pruritic papules on exposed skin areas, often in mornings, but may appear several days after exposure.

Papules are usually in a linear pattern representing several sequential blood meals.

Management is symptomatic with topical corticosteroids, oral antihistamines as needed, and evaluation for secondary infection. Eradication requires environmental inspection and appropriate pest management; routine antibiotics or insecticide application to the patient are not indicated.

Scabies

Sarcoptes scabiei: Scabies mite.

Small, intensely pruritic papules.

Often in linear patterns representing burrows.

Permethrin 5% cream is first-line for most patients aged 2 months or older; apply according to the labeled regimen (typically neck down for 8–14 hours, with age-specific attention to scalp/face when needed), then repeat after approximately 7 days if indicated. Oral ivermectin is an alternative for appropriate patients; a second dose 7–14 days later is needed because it does not reliably kill eggs. Treat close contacts at the same time and clean bedding and clothing. Persistent itching alone for several weeks does not necessarily signify treatment failure. [11]

Crusted scabies requires urgent specialist-directed combined therapy and infection-control measures because it is highly contagious.

Other Stinging and Biting Insects

Mosquitoes, flies, fleas, ticks, and spiders all rely on blood meals and can introduce substances to enhance their ability to feed.

Remove retained stingers or ticks promptly with suitable technique, clean the site, and use cold compresses or topical antipruritics for local reactions. Do not use routine antibiotics unless secondary bacterial infection is evident. Review vector-borne disease risks by geography, season, exposure, and symptoms. If fever, severe headache, joint symptoms, spreading rash, neurologic findings, or systemic allergic symptoms develop, reassess promptly.

Tick-bite prophylaxis for Lyme disease applies only to selected high-risk Ixodes exposures within 72 hours of removal; it is not recommended as routine prophylaxis for RMSF. [2], [12]

Dermatophyte Infections and Annular Eruptions

Tinea Corporis

Pruritic, circular or oval, erythematous scaling plaque that spreads centrifugally to form an annular lesion with central clearing and an erythematous scaly border.

Single or multiple lesions; multiple lesions may coalesce to form "flower petal" configurations.

Treat limited disease with an appropriate topical antifungal, such as terbinafine or clotrimazole, according to label instructions for approximately 2–4 weeks. Potassium hydroxide (KOH) microscopy may confirm uncertain diagnoses. Do not use topical steroid monotherapy or steroid–antifungal combination products for suspected tinea; they can mask or worsen infection. Extensive, recurrent, or refractory disease may require fungal testing and oral treatment. [13]

Tinea Capitis and Kerion

Tinea capitis almost always presents in children; seborrhea or other inflammatory disorders in adults may mimic tinea infection and be misdiagnosed.

Often includes hair breakage near the scalp.

Scalp dermatophyte infection requires systemic antifungal therapy; topical preparations alone are ineffective. Oral terbinafine or griseofulvin is selected according to organism, age, weight, medication risks, and availability, often for 4–8 weeks or longer. Obtain fungal testing when practical, and arrange follow-up to document response. [13]

Boggy, tender kerion may cause permanent alopecia if treatment is delayed. Distinguish kerion from bacterial abscess; prompt systemic antifungal treatment and specialty follow-up are important, with urgent assessment for systemic illness or secondary infection. [13]

Tinea Pedis and Tinea Cruris

Occurs and flares particularly with sweating of the feet and in the crural folds.

Intensely pruritic.

Treat limited tinea pedis or cruris with an appropriate topical antifungal, keeping affected folds dry and avoiding sharing towels or footwear. Consider KOH examination for uncertain or refractory lesions. Oral treatment may be required for extensive disease, severe moccasin-type tinea pedis, immunocompromise, or failure of topical therapy. [13]

Dermatophytid (Id) Reactions

The reactions are a secondary immunologic response to fungal antigens or delayed hypersensitivity.

These are pruritic, papulovesicular eruptions that can be distant from the site of infection.

Treat the underlying dermatophyte infection; topical corticosteroids and antipruritic measures can relieve the distant inflammatory eruption. Reassess if the distribution or systemic findings suggest a drug eruption, dyshidrotic eczema, or another diagnosis.

Tinea Versicolor

Malassezia furfur, a yeast—not a dermatophyte infection as the name might imply.

Small, discolored, either hypopigmented or hyperpigmented patches.

Tinea versicolor is caused by Malassezia species. Topical selenium sulfide or ketoconazole preparations are appropriate for most patients; oral antifungals are reserved for extensive or refractory disease after considering safety and interactions. Pigment changes may persist after the yeast is cleared. [13]

Granuloma Annulare

Localized: Nonscaly, erythematous annular plaque on the distal extremities.

Most resolve spontaneously within several years.

Typical localized lesions often require only reassurance. Consider dermatology referral for uncertain diagnosis, widespread disease, rapid change, or symptomatic lesions. Biopsy may be necessary when lesions are atypical or cannot be distinguished from tinea or another annular disorder.

Pyogenic Granuloma

Small red papules that rapidly grow over weeks to months and then stabilize.

Lesions bleed profusely with minor trauma; ulceration is possible.

These vascular growths may require removal or cautery by an appropriately trained clinician with hemostasis capability. Rapidly growing, atypical, pigmented, recurrent, or nonhealing lesions require histologic evaluation to exclude malignancy. Avoid assuming all friable red papules are benign.

Urticaria

Blanching, erythematous, circumscribed, or polymorphous smooth plaques of varying sizes; can have central pallor.

Often transient or waxing and waning in intensity, number, and distribution of lesions.

Acute, <6 weeks' duration; chronic, >6 weeks' duration.

For isolated urticaria without anaphylaxis, use a nonsedating second-generation H1 antihistamine such as cetirizine or loratadine, with follow-up as needed. Routine systemic corticosteroids and H2 blockers are not foundational treatment. Assess for airway symptoms, wheeze, hypotension, repetitive vomiting, or cardiovascular compromise; suspected anaphylaxis requires immediate intramuscular epinephrine and EMS transfer. [14]

Macular and Maculopapular Rash Patterns

The vast majority of blanching macular and maculopapular rashes are related to viral and other infectious etiologies.

Viral exanthems often require supportive care, but the pattern must be interpreted with immunization history, drug exposure, pregnancy, travel, fever, and systemic findings. Isolate and consult public health when a high-consequence communicable illness is suspected.

Erythema Infectiosum (Fifth Disease)

Parvovirus B19.

Facial "slapped cheek" rash, often with circumoral pallor.

Macular lacelike rash with centrifugal progression from trunk to arms, buttocks, or thighs.

Care is usually supportive in otherwise healthy children, who are generally no longer contagious after the rash appears. Parvovirus B19 infection may cause severe anemia in hemolytic disorders or immunocompromised patients and fetal complications after maternal infection; these situations warrant prompt evaluation and appropriate obstetric or hematology consultation.

Exanthema Subitum (Roseola Infantum)

Human herpesvirus 6.

Erythematous macular or maculopapular rash that is most prominent on the neck and trunk.

The classic sequence is several days of high fever followed by defervescence and a transient rash in a generally improved child. Supportive care is sufficient when the child is well; assess any ill-appearing infant or persistent fever independently rather than diagnosing roseola solely from the pattern.

Rubeola (Measles)

The measles virus (RNA Morbillivirus).

"3 Cs and 1 K": Cough, Coryza, Conjunctivitis, and Koplik spots.

Suspected measles requires immediate airborne isolation, mask/source control when possible, and public health notification. Arrange testing with a respiratory specimen for RT-PCR and serum IgM as directed; do not leave a potentially infectious patient in a routine waiting room. Management is supportive, with higher-level care for respiratory distress, dehydration, encephalitis, or other complications. Public health determines exposure notification and postexposure prophylaxis. [15]

Rubella ("German Measles")

Maculopapular rash with a low-grade fever and lymphadenopathy (especially cervical and occipital).

The rash initially appears on the face, with cephalocaudal progression to the trunk and extremities.

Because maternal infection may result in serious congenital disease, promptly notify public health of suspected cases, arrange confirmatory testing through recommended pathways, and address pregnancy exposure and isolation. Vaccination history and local epidemiology are essential to assessment. [15]

Other Viral Infections With Maculopapular Exanthema

Adenovirus: Respiratory symptoms, conjunctivitis, pharyngitis.

Epstein-Barr virus: "Mononucleosis syndrome"; pharyngitis, adenopathy, hepatosplenomegaly.

Cytomegalovirus: "Mononucleosis syndrome," causing a febrile illness with lymphadenopathy.

Enteroviruses include echoviruses, coxsackieviruses, rhinoviruses, and polioviruses.

Clinical pattern and associated symptoms determine whether specific testing is useful. Examine for meningismus, dehydration, respiratory compromise, hepatitis, or other concerning features; stable uncomplicated viral exanthems are generally managed supportively. Infection-control requirements vary by pathogen.

Scarlet Fever

An exotoxin-producing strain of GABHS.

Characteristic confluent erythematous rash with a fine sandpaper texture.

Confirm group A streptococcal infection with an appropriate rapid test or culture before treatment. If a rapid antigen test is negative in a symptomatic child aged 3 years or older, a backup throat culture is usually indicated. Treat confirmed scarlet fever with penicillin or amoxicillin; one CDC pediatric amoxicillin regimen is 50 mg/kg orally once daily (maximum 1 g) for 10 days. [16]

Perineal or Perianal Streptococcal Dermatitis

Perianal or perineal edema, tenderness, and pruritus.

Superficial, well-demarcated perineal or perianal erythema.

Consider perianal group A streptococcal infection in a child with painful defecation, pruritus, fissures, or bright red sharply demarcated erythema. Swab affected skin for bacterial testing when available, treat confirmed infection with an appropriate systemic antibiotic, and reassess for recurrence or alternative diagnoses.

Streptococcal or Staphylococcal Toxic Shock and Erythroderma

Rapid-onset hypotension and septic shock with multiorgan system dysfunction.

Fever, diffuse erythroderma, hypotension, severe pain, or rapidly progressive soft-tissue infection may indicate toxic shock syndrome or another invasive infection. Activate EMS, begin stabilization within local capabilities, and arrange immediate hospital management including cultures, parenteral antibiotics, and source control; do not attempt outpatient management. [1]

Erythema Marginatum

One of the 5 major Jones criteria for the diagnosis of rheumatic fever.

Evanescent, pink, nonpruritic rash involving the trunk and extremities but not the face.

Consider acute rheumatic fever with compatible migratory arthritis, carditis, chorea, nodules, or recent streptococcal infection. Suspected cases need further cardiac and infectious evaluation in coordination with appropriate specialty care; the skin finding alone is not diagnostic.

Erythema Nodosum

The rash begins with red or violet painful subcutaneous nodules that most typically present in the pretibial region.

The rash resolves into bruise-like lesions that resolve within 2 to 8 weeks.

Common triggers include streptococcal infection, medications, sarcoidosis, inflammatory bowel disease, pregnancy, and other infections. Evaluation is guided by associated symptoms and risk factors; supportive management may be sufficient for mild cases, with referral for severe, persistent, or recurrent disease.

Kawasaki Disease

Kawasaki disease is one of the most common vasculitides of childhood, but its etiology is unknown.

Consider Kawasaki disease in young children with persistent fever and compatible conjunctival injection, oral changes, extremity findings, rash, or cervical lymphadenopathy; incomplete Kawasaki disease is possible, especially in infants. Same-day emergency/pediatric evaluation is warranted for suspected cases because coronary complications require timely echocardiography and hospital-directed therapy. The 2024 AHA statement emphasizes early recognition and intensified treatment in high-risk patients. [17]

Multisystem inflammatory syndrome in children (MIS-C) may resemble Kawasaki disease after SARS-CoV-2 infection and should enter the differential when fever, gastrointestinal symptoms, shock, or cardiac abnormalities are present.

Erythema Migrans (Early Lyme Disease)

The rash is related to Lyme disease, which is transmitted by deer ticks (Ixodes scapularis) carrying the spirochete Borrelia burgdorferi.

Erythema migrans is an expanding lesion that often lacks classic central clearing. In an endemic setting with plausible exposure, a typical rash is a clinical diagnosis and should be treated without waiting for serology, which may be negative early. Adult treatment options include doxycycline 100 mg orally twice daily for 10 days or amoxicillin 500 mg three times daily for 14 days; pediatric regimens are weight-based. Neurologic, cardiac, or other disseminated symptoms require additional evaluation. [12]

Immune-Mediated Dermatitis and Mucositis

Erythema Multiforme

Fewer than 90% of cases are secondary to infection (e.g., HSV, mycoplasma); fewer than 10% of cases are secondary to drug reaction (e.g., penicillins, sulfonamides, NSAIDs, barbiturates).

"Target lesions": Erythematous papules that expand into plaques with dusky violaceous centers.

Erythema multiforme is distinct from Stevens–Johnson syndrome and toxic epidermal necrolysis, rather than simply an earlier grade of the same disease. Characteristic fixed target lesions, often acral, commonly follow HSV infection. Provide supportive care for mild cutaneous disease; significant oral involvement, ocular symptoms, dehydration, or an uncertain diagnosis requires urgent evaluation. [18]

Stevens–Johnson Syndrome and Toxic Epidermal Necrolysis

Severe immune-mediated reaction, usually to medications (anticonvulsants, sulfonamides, NSAIDs) or infection (mycoplasma).

Skin pain, dusky or atypical target-like lesions, blistering, epidermal detachment, and mucosal erosions after a new medication should raise immediate concern for SJS/TEN. It is a potentially fatal emergency. Discontinue a suspected culprit drug if clinically appropriate, activate EMS, and arrange hospital assessment; do not wait for a skin biopsy before transfer. [18]

SJS and TEN are classified along a spectrum according to epidermal detachment (SJS <10%; overlap 10%–30%; TEN >30% of body surface area). Initial urgent care management centers on recognition, stabilization, and careful transfer rather than outpatient systemic corticosteroid treatment. Eye involvement requires urgent ophthalmologic expertise. [18]

Vesicular, Bullous, Ulcerative, and Crusting Rashes

Many of these exanthems also have specific patterns, time courses, and associated findings that are diagnostic of the underlying illness. Recognizing these patterns is important for clinical diagnosis.

Herpes Simplex Virus Infections

HSV type 1 or 2.

Papules progress to vesicles within 24 hours and then form adherent eschars (crusts) in 8 to 10 days.

HSV testing by lesion swab nucleic acid amplification is preferred when confirmation is necessary; Tzanck smear is insensitive and cannot type the virus. Oral acyclovir, valacyclovir, or famciclovir may shorten symptomatic mucocutaneous outbreaks when started promptly, with selection based on location, episode type, host risk, and renal function. [19]

Herpes Labialis

Local skin eruption can present and spread anywhere on the body or in mucous membranes, including the eyes and genitalia.

Recurrent cold sores often respond to episodic antiviral therapy started at the first tingling or burning symptom. Provide counseling on transmission during active lesions and oral contact. Severe disease or unusual lesions in an immunocompromised patient warrant further evaluation.

Eczema Herpeticum

Classic "punched-out" lesions superimposed on areas of eczema, often to the face.

Painful, monomorphic vesicles or erosions with fever on atopic skin may represent disseminated HSV infection. Prompt systemic antiviral treatment and urgent evaluation are indicated; eye involvement or extensive/systemic disease generally requires emergency referral and sometimes IV acyclovir. [19]

Herpetic Keratitis

Associated eye pain, conjunctivitis, discharge.

Dendritic corneal lesions on fluorescein examination suggest HSV keratitis. Suspected infection requires same-day ophthalmologic assessment. Avoid topical corticosteroids without ophthalmology direction and do not delay assessment for vision loss, photophobia, or severe pain. [19]

Herpetic Whitlow

Vesicular eruption around the nail bed, cuticle, or distal phalanx.

Differentiate herpetic whitlow from bacterial felon or paronychia. Do not incise and drain HSV lesions. Cover lesions and provide analgesia; consider oral antivirals when early, severe, or recurrent, with specialist assessment for atypical disease. [19]

Herpetic Stomatitis

Intraoral ulcerations, typically seen in the anterior mouth (gingiva, buccal mucosa, inner lip).

Treat pain and encourage frequent fluids. Oral acyclovir may benefit appropriately selected children with early primary severe gingivostomatitis. Avoid compounded anesthetic mixtures that risk accidental lidocaine ingestion; dehydration, inability to swallow, severe illness, or immunocompromise requires escalation.

Varicella-Zoster Virus Infections

Varicella-zoster virus (VZV) of the herpesvirus family.

As with other herpesviruses, varicella causes primary infection and remains dormant in the sensory nerve ganglia; it can be reactivated later in life.

Diagnosis is often clinical; PCR of vesicular or crusted lesion material is preferred when confirmation is important. Assess immune status, pregnancy, age, and respiratory/neurologic complications. [20]

Primary Varicella ("Chickenpox")

"Dew drops on a rose petal": Crops of vesicles on erythematous bases.

Progression to pustules, then crusts; lesions in crops will be in different stages of development.

Otherwise healthy children with uncomplicated varicella generally require supportive care, skin hygiene, and fever management. Avoid aspirin in children. Oral antiviral treatment may be considered for selected higher-risk patients if begun promptly; severe, disseminated disease or infection in significantly immunocompromised patients requires hospital management and often IV acyclovir. [20]

Postexposure prevention depends on evidence of immunity, risk, and timing. Varicella vaccination can be given to eligible exposed patients; VariZIG may be appropriate for susceptible high-risk people who cannot receive vaccine, as soon as possible and within 10 days after exposure. [20]

Atypical or Breakthrough Varicella

Mild variant illness that can occur in immunized individuals.

Breakthrough varicella may be less vesicular and present with fewer lesions, but remains contagious. Consider PCR when differentiation from other viral rashes affects management or outbreak control; follow appropriate exposure precautions and reporting guidance.

Herpes Zoster ("Shingles")

Reactivation of VZV from the nerve root.

There is vesicular eruption with dermatomal distribution; most often it is truncal, but it can appear elsewhere, such as in the distribution of the trigeminal nerve of the face.

Initiate an appropriate oral antiviral promptly, ideally within 72 hours of rash onset, and consider treatment beyond that window for new lesions, significant complications, or high-risk patients. Typical adult options include valacyclovir 1 g orally three times daily for 7 days, with renal dose adjustment when indicated. Disseminated or complicated zoster requires hospital assessment. Vaccination recommendations should be checked against current ACIP guidance. [20]

Herpes Zoster Ophthalmicus

Zoster lesions in the ophthalmic (V1) distribution, particularly with eye pain, red eye, photophobia, visual change, or nasal-tip lesions, warrant immediate antiviral treatment and same-day ophthalmologic evaluation. Facial distribution alone does not reliably exclude eye involvement. Do not delay referral for a negative or limited urgent care examination.

Hand-Foot-and-Mouth Disease

Coxsackievirus (most commonly Coxsackie group A).

Distinctive exanthem pattern with ulcers and vesicles in the oral cavity (especially on the tongue and cheeks) and vesicles on hands, feet, buttocks, and genitals.

HFMD is caused by several enteroviruses and is managed primarily with hydration, appropriate analgesia, and infection-control counseling. Avoid routine antibiotics and potentially toxic topical oral anesthetic mixtures, especially in young children. Dehydration, neurologic findings, or an ill appearance requires emergency assessment.

Impetigo

Staphylococcus aureus and GABHS.

Papules on an erythematous base that progress to vesiculopustules and subsequently form classic "honey-colored" crusts; the face and extremities are often affected.

Limited nonbullous impetigo can be treated with topical mupirocin or retapamulin; numerous lesions, outbreaks, ecthyma, or surrounding cellulitis may require systemic therapy active against likely streptococci and staphylococci. Routine cultures are unnecessary for typical localized cases, but may help in recurrent or treatment-resistant disease. [21]

Neonates

Skin rashes and lesions in newborns are a frequent presenting complaint to primary care and urgent care providers. These findings are generally benign and self-limited, requiring only supportive treatment and caregiver reassurance.

The presence of fever or hypothermia, poor feeding, lethargy, vesicles, pustules, purpura, rapidly spreading erythema, or a toxic appearance in a neonate demands prompt assessment for serious bacterial or HSV infection. Do not label an ill neonate's eruption benign on morphology alone.

Erythema Toxicum Neonatorum

Multiple erythematous macules and papules, 1 to 3 mm in diameter, over the trunk and proximal extremities, sparing the palms and soles, and progressing to pustules on an erythematous base.

Appearance within 24 to 48 hours after birth, with spontaneous resolution in 5 to 7 days.

A well, afebrile newborn with typical lesions requires no treatment. Pustules in an ill or febrile infant need urgent evaluation rather than reassurance.

Neonatal and Infantile Acne

Acneiform lesions, including comedones, inflamed papules, and pustules on the face.

Mild neonatal cephalic pustulosis and infantile acne often improve with gentle cleansing and observation. Persistent inflammatory acne, nodules, scarring, severe early onset, or signs of androgen excess require pediatric or dermatology evaluation; medications should be age-appropriate and used cautiously.

Transient Neonatal Pustular Melanosis

Most common in full-term, dark-skinned infants.

Three stages of lesions: Small pustules progressing to erythematous macules with scaly collarettes and then to hyperpigmented macules that gradually fade.

The eruption is benign in an otherwise well neonate and needs no treatment; review for infectious causes if the presentation or general condition is atypical.

Infantile Seborrheic Dermatitis (Cradle Cap)

Yellow, greasy scales often overlying erythematous, scaly, salmon-colored plaques primarily on the scalp.

Gentle cleansing, emollients, and soft brushing help loosen adherent scale. A brief course of mild topical anti-inflammatory treatment may be used for significant inflammation under clinical supervision. Widespread, persistent, or atypical rash should prompt reconsideration of the diagnosis.

Congenital Dermal Melanocytosis (Previously "Mongolian Spots")

Congenital blue-gray macules or patches with ill-defined borders; most often found in the sacral region and on the buttocks, across shoulders, or across the upper back.

Use the term congenital dermal melanocytosis. These birthmarks are benign and commonly fade over years; document site, size, and appearance to distinguish them from bruising. Extensive or atypically distributed lesions merit individualized evaluation.

Infantile Hemangioma

Benign vascular tumors characterized by a proliferation of blood vessels.

Often not evident at birth; can become apparent within the first days to months of life.

Unlike the original wait-and-see approach, high-risk hemangiomas need early specialist assessment—ideally by one month of age—because proliferation can threaten vision, feeding, breathing, or cause ulceration and permanent changes. Oral propranolol is first-line systemic treatment when indicated; topical timolol is an option for select thin superficial lesions under appropriate guidance. [22]

Segmental facial lesions, periocular or airway-associated lesions, multiple cutaneous hemangiomas, large lumbosacral lesions, and ulceration warrant referral or additional evaluation based on clinical risk.

Umbilical Granuloma

Excess granulation tissue at the healing umbilical stump.

Can be sessile or pedunculated.

A small moist pink umbilical granuloma in an afebrile, well infant can often be managed with carefully applied silver nitrate by a trained clinician, protecting surrounding skin from burns. Persistent drainage, urinary or feculent discharge, an umbilical mass, or failure to resolve suggests a polyp or congenital tract and requires referral. Periumbilical cellulitis, fever, or an ill neonate requires emergency evaluation. [23]

URGENT CARE DISPOSITION PEARLS

Provide clear return precautions: worsening rash, new fever, skin pain, mucosal sores, facial or eye involvement, severe headache, altered mental status, hypotension, difficulty breathing, rapidly spreading purpura, dehydration, or new systemic symptoms. Short-interval reassessment is appropriate when the diagnosis is uncertain but the patient is currently stable.

MEDICOLEGAL PEARLS

Any child (particularly if they are ill-appearing) who presents with a fever and a petechial rash must be considered to have meningococcemia until proven otherwise.

Document overall appearance, vital signs, whether lesions blanch, distribution, mucosal findings, and progression; record the specific rationale for transfer or outpatient management. Do not allow an initially benign appearance to override rapidly worsening symptoms or concerning exposure history.

Any infant or neonate with a serious or toxic symptom (fever, poor feeding, a change in level of consciousness) with or without skin eruptions must have a sepsis evaluation.

Document communicable-disease isolation and reporting steps when measles, meningococcal disease, or other reportable illness is suspected. Obtain appropriate guardian permission for clinical photography and document child-safety concerns objectively, including anatomic location and measurements of patterned bruising.

Confirm the exact medication, concentration, dose, duration, patient weight, age, allergies, immune status, pregnancy status, and available follow-up before prescribing. Treatment pathways intended for emergency departments or inpatient facilities should not be portrayed as urgent-care-only alternatives.

Keywords

Dermatologic conditions; rash; urgent care; petechiae; purpura; cellulitis; eczema; psoriasis; dermatophytes; scabies; measles; Stevens–Johnson syndrome; herpes zoster; infantile hemangioma; pediatric dermatology.

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