Lichen Planopilaris with Pustules: A Diagnostic Challenge.

Introduction: Lichen planopilaris (LPP) is a lymphocytic primary cicatricial alopecia presenting with scarring hair loss and variable degrees of perifollicular erythema and scaling. Pustules are infrequent and may mimic folliculitis decalvans (FD) and other forms of neutrophilic alopecia. We present a series of LPP cases with pustules and discuss the importance of differentiating them from primary neutrophilic folliculitis.

Materials And Methods: Demographic, clinical, histopathological, and follow-up data of 13 cases of LPP with pustules followed at the Department of Dermatology of the University of São Paulo Medical School were described.

Results: Seven females and 6 males were included. Onset of signs and symptoms ranged from 23 to 61 years of age. Previous diagnoses were FD in 3 patients, pityriasis amiantacea in 2 cases, and folliculitis keloidalis nuchae in 1 case. Other 7 cases presented typical clinical features of LPP.

Discussion: There is limited data concerning LPP with pustules. Our analysis shows that LPP should be considered a differential diagnosis in patients with refractory folliculitis. Cautious examination of the entire scalp with dermoscopy and/or reevaluation after a course of antibiotics can avoid misdiagnosis. Further studies are required to establish the etiology of pustules in the setting of LPP.