Actinic superficial folliculitis was first described in 1985, and since then only three reports have been published. Clinically and histopathologically this disease is very particular and has been suggested to be considered as an entity. We report on a 30-year-old man who presented with an extensive superficial follicular pustulosis on his back, shoulders and upper chest after exposure to intense heat and subsequent sweating on a sunny day. The pustules arose within 24-36 h afterwards. Histology and immunohistochemistry revealed subcorneal pustules, suppurative folliculitis and an infiltrate consisting of T cells, macrophages and neutrophils around the hair follicle, sebaceous glands and small vessels. To the best of our knowledge this is the fourth report on actinic superficial folliculitis and the first on which a characterization of the inflammatory infiltrate has been performed. Because of the impressive, unique symptoms and the characteristic histology we agree with those who have suggested that actinic superficial folliculitis is a new entity.