53-Year-Old Woman With Dark Patchy Spots on Face and Neck

Published on December 31, 2025

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Differential Diagnosis

• Pellagra
• Pigmented contact dermatitis
• Lichen planus pigmentosus
• Post-inflammatory hyperpigmentation
• Lichenoid drug eruption
• Subacute cutaneous lupus erythematosus

Diagnosis

The correct diagnosis is lichen planus pigmentosus (LPP), a rare variant of lichen planus (LP).  It is thought to be a hypersensitivity reaction to an unknown antigen leading to lichenoid inflammation and subsequent superficial dermal hyperpigmentation. LLP is most often a self-limiting disorder more commonly seen in adults over the age of 30, and among women and patients with darker skin tones. LPP typically presents with gray-brown or dark brown macules or patches most often found in sun-exposed or flexural areas, and pruritis is typically absent or minimal. Treatment is focused on accelerating resolution and managing pruritis, if present.

What to Look For

• A comprehensive history should be taken including a list of current medications, presence of oral or genital erosions, and dysphagia or odynophagia.
• The dermatologic exam should include the entire cutaneous surface, including the scalp, oral cavity and external genitalia.
• If available, a punch or shave biopsy reaching the depth of the mid-dermis is appropriate to confirm the diagnosis.

Pearls for Urgent Care Management

• Evidence suggests an association between LP and Hepatitis C (HCV) infection; testing for HCV infection may be appropriate if other risk factors are present.
• First line therapy is topical corticosteroids
  • High potency cream or ointment twice daily for localized patches on the truck and extremities
  • Mid or low potency cream or ointment twice daily on intertriginous or facial skin
  • Efficacy should be assessed after two or three weeks.
• If pruritis is present, oral antihistamines may be helpful
• Patients should be cautioned about the risk for cutaneous atrophy with use of topical steroids
• Referral to dermatology is appropriate if topical steroids are not effective. Patients with refractory LP lesions may benefit from other treatments such as oral glucocorticoids, phototherapy and oral acitretin.