BACKGROUND: It is general opinion that histopathology is nonspecific and of little value in diagnosing erosive pustular dermatosis of the scalp (EPDS).
OBJECTIVES: Clinicopathologic correlation of erosive pustular dermatosis of the scalp.
METHODS: The clinical and pathological records of patients with a clinicopathologic diagnosis of EPDS, between 2011-2016, at the Dermatopathology Unit of the Turin University were reviewed.
RESULTS: Thirty elderly patients with EPDS were identified, 22 males and 8 females. Androgenetic alopecia was present in 19/30 patients. Triggering factors included mechanical trauma in 10/30 cases, surgical procedures in 4/30, herpes zoster in 1/30. Three patients were affected by autoimmune disorders. The vertex was the most common location. Disease presentation varied markedly from tiny, erosive, scaly lesions to crusted and hemorrhagic plaques, mimicking pustular pyoderma gangrenosum. The pathologic changes differed according to the lesion type and disease duration. Interestingly, a spongiotic and suppurative infundibulo-folliculitis was observed in 8/30 cases.
LIMITATIONS: This was a retrospective study.
CONCLUSIONS: We believe that the primary lesion of erosive pustular dermatosis of the scalp is a spongiotic, pustular superficial folliculitis. The clinicopathologic similarities with other neutrophilic dermatoses, such as pustular pyoderma gangrenosum, suggest this condition should be included in this spectrum, where pathergy plays a pathogenetic role.