DP16: Scarring alopecia masquerading as follicular mucinosis as a side-effect of chronic topical steroid therapy: a case report

Faris Kubba,¹ Bindi Gaglani,² Meghna Shetty² and Nasim Rouhani²

¹Ealing Hospital, London North West University Healthcare NHS Trust, London, UK; and ²Northwick Park Hospital, London North West University Healthcare NHS Trust, London, UK

We present a case of a 37-year-old white male who had a 2-year history of a severely pruritic scaly erythematous area of scarring alopecia with papules on the vertex. Over time, he developed papules and pustules around the site of alopecia following treatment with topical Dermovate and Protopic. The clinical differential diagnosis included lichen planopilaris, discoid lupus erythematosus and pustular folliculitis. Three biopsies of the scalp vertex were performed, and they have all shown similar features. On horizontal sections there was follicular fibrosis with some free-lying hair follicles, foreign body giant cell reaction to ruptured follicles and mild perifollicular lymphocytic infiltrate with tufted hair follicles. On Alcian blue stain there was a thin layer of perifollicular mucin, as well as in the surrounding elastolytic dermis. The vertical sections showed a diffusely scarred upper dermis and similar findings in the deep dermis. The basement membrane zone was not thickened and no follicular keratin plugging was seen. Direct immunofluorescence and antinuclear antibodies tests were negative. Our working diagnosis was that of an active scarring alopecia, favouring an advanced stage of lichen planopilaris. The presence of abundant mucin is a side-effect of chronic topical potent steroids over 2 years. This may give a false impression of alopecia mucinosa; however, the extensive scarring and perifollicular inflammation are not features of this condition. Furthermore, no other features of active cutaneous discoid lupus erythematosus were noted to justify the presence of mucin. Prolonged topical steroid use can cause dermal changes in extracellular matrix and fibrillary component of collagen and elastin. Being aware of such a side-effect is important and stopping steroids for at least several weeks before performing the biopsy is always indicated to achieve the best yield. The elastolysis seen in similar conditions after chronic topical applications can be very misleading as in our case, and may interfere with achieving the correct diagnosis.