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Differential Diagnosis
- Bacterial folliculitis
- Eosinophilic folliculitis
- Seborrheic dermatitis
- Pityrosporum folliculitis
- Acne vulgaris
- Pruritic papular eruption (PPE)
- Scabies
Diagnosis
The correct diagnosis is eosinophilic folliculitis (EF), a relatively common skin eruption in patients with advanced human immunodeficiency virus (HIV) disease. Since the advent of antiretroviral therapy (ART), EF has become less common. The etiology of EF is unclear, but may be related to immune dysregulation, possibly in association with an underlying infection or autoimmune response. EF is associated with low CD4 counts (often below 250) and later-stage HIV disease. It is characterized by a pruritic skin eruption consisting of follicular papules or pustules, predominantly located on the scalp, face, neck, and upper chest. EF is a clinical diagnosis which can also be confirmed via skin biopsy; a 4 mm punch biopsy of an unexcoriated lesion is usually sufficient for histological confirmation.
What to Look For
- EF is characterized by recurrent, pruritic crops of discrete, erythematous, dome-shaped follicular papules and rare pustules, with a diameter of 3 to 5 mm.
- The most common areas of involvement are those with a high concentration of sebaceous glands: the scalp, neck, and upper trunk.
- Facial involvement is particularly common in female patients with EF.
- Intense and intractable pruritus is typical.
- Peripheral eosinophilia and elevated serum IgE are seen in about 25 to 50 percent of patients with HIV-associated EF; these tests are not needed for diagnosis.
- Chronicity can lead to prurigo and protracted post-inflammatory hyperpigmentation, especially in patients with darker skin tones.
Pearls For Urgent Care Management
- ART management of HIV is the primary first-line therapy for EF. Subsequent rise in CD4 count is often associated with improvement or resolution of symptoms.
- There are reports of EF flaring during the first 2 – 6 months of ART, consistent with immune reconstitution inflammatory syndrome (IRIS).
- Treatment of pruritis: High potency topical steroids (and lower potency formulations for lesions on the face) can be used for EF-associated pruritic. Oral antihistamines can also be prescribed, but neither will suppress the development of new lesions, and often do not fully control symptoms.
- Although oral glucocorticoids can improve HIV-associated EF, relapses are common within a few weeks after course completion and long-term treatment is associated with risk for serious side effects.
- For patients with recurrent symptoms not responding to treatment, a referral to dermatology is appropriate as phototherapy is often offered as a second-line therapy.