Erosive pustular dermatosis of the scalp: reappraisal of an underrecognized entity.

Erosive pustular dermatosis of the scalp (EPDS) is an inflammatory dermatosis of unknown etiology. Herein, we present a review of the disease and report our own clinical and histopathological experience in eleven patients. EPDS tends to spontaneously affect bald areas of the scalp in elderly individuals. A history of previous surgery at the same site - as observed in four of our patients - is common. Coronary artery disease, cerebrovascular insult, arterial hypertension, diabetes mellitus, and severe cases of cancer were frequent comorbidities. Most patients show an undulating clinical course despite topical anti-inflammatory treatment; in some individuals, the lesions heal with scarring. Histopathology reveals scaly crusts or erosions and granulation tissue-like changes in the dermis, evolving into a scar in more advanced stages. Apart from actinic/local damage, impaired immunity and microcirculation may be predisposing factors of the disease. Similar to pyoderma gangrenosum, EPDS must be considered in the context of nonhealing wounds in the elderly after the differential diagnoses mimicking EPDS have been ruled out. Given that previous or concomitant adjacent basal cell or squamous cell carcinoma is a common finding and that infiltrative variants extending beyond the clinically visible tumor may occur, histological mapping of the surrounding skin may be advisable in doubtful cases.