TNF-inhibitor associated psoriatic alopecia: Diagnostic utility of sebaceous lobule atrophy

The increasingly successful and widespread use of Tumor Necrosis Factor inhibitors (TNFi) to treat autoimmune and inflammatory conditions has also been accompanied by adverse reactions, both systemic and cutaneous. Psoriasiform cutaneous rashes are well described. Recently, TNF inhibitor associated psoriatic alopecia (TiAPA) is being more frequently reported. The purpose of this study is to describe the features of TiAPA, including marked atrophy of sebaceous lobules as a histologic clue to diagnosis, helping to distinguish it from other types of alopecia. Clinical and histopathological features of 3 patients who developed scalp alopecia while on TNFi treatment were examined. Clinical follow up was conducted after discontinuation of TNFi. A review of the previous literature on the subject was also conducted. Atrophy of sebaceous lobules is a potentially reversible, characteristic and conspicuous feature of TiAPA that can be distinguished from idiopathic psoriatic alopecia by clinical history of drug exposure and sometimes by histologic presence of a mixed inflammatory response including plasma cells and eosinophils.