Horny perifollicular mucinosis. An atypical pityriasis rubra pilaris-like eruption associated with HIV infection.

We present a case of pityriasis rubra pilaris (PRP)-like eruption, in association with human immunodeficiency virus (HIV) infection, clinically characterized by follicular papules with some elongated spines and comedo-like lesions. The lesions were located on the back, flanks, and proximal extremities. Orthokeratotic follicular plugs and perifollicular mucinous degeneration were consistently observed on three biopsies. The most characteristic histological features of PRP were absent. To our knowledge, this is the first reported case of this kind. Such a case could suggest an atypical PRP modified by HIV infection. It is also possible that it represents a new entity associated with advanced HIV infection (horny perifollicular mucinosis).