Scarring alopecia

Specialty: Skin.

• definitive hair loss with follicular destruction
• scarring baldness

Why it occurs

• Lichen planus pilaris (lichenoid profile inflammation directed against the stem cells of the hair follicle in the bump)
• Chronic discoid lupus erythematosus (cutaneous autoimmunity with deposition of immune complexes at the follicular dermoepidermal junction)
• Folliculitis decalvans (chronic and destructive bacterial infection by *Staphylococcus aureus* with neutrophilic inflammation)
• Dissecting cellulitis of the scalp (suppurative panniculitis with formation of sinuous tracts)
• Severe physical trauma, thermal burns or previous radiotherapy to the skull.

Initial workup

Digital trichoscopy (showing the absence of follicular orifices, perifollicular erythema, sheath peeling and keratotic plugs). Skin biopsy with a 4 mm punch of the active edge of the alopecic plaque, ideally processed with horizontal and vertical cuts for immunofluorescent histopathological study.

Standard management

• Clobetasol propionate 0.05% in foam or solution — topical corticosteroid of choice to stop the initial inflammatory infiltrate
• Triamcinolone acetonide in suspension — intralesional infiltration of 5-10 mg/mL into the active edges of the plaque every 4 weeks
• Hydroxychloroquine — synthetic antimalarial with immunomodulatory properties of choice in lichen planus pilaris or discoid lupus, dose of 200 to 400 mg/day orally, with annual ophthalmological examination
• Doxycycline (tetracycline for oral use for its anti-inflammatory and antibacterial effect in folliculitis decalvans, 100 mg every 12 hours).