Erosive Pustular Dermatosis of the Scalp: Clinicopathological Correlation Leading to a Definition of Diagnostic Criteria

Abstract

Introduction. Erosive pustular dermatosis of the scalp (EPDS) is frequently misdiagnosed as epithelial tumor or trauma. To the authors’ knowledge, no international guidelines or consistent recommendations for treatment of EPDS exist, and histological findings often are labeled as nonspecific. Objective. This study aimed to identify clinical and histological characteristics unique to EPDS to aid diagnosis. Materials and Methods. The biopsies of 21 patients (age range, 73–90 years) with EPDS and who were diagnosed and treated at the Department of Dermatology at University of Leipzig Medical Center and the Asklepios Medical Center, Weißenfels, Germany, were reevaluated by dermatopathologists. Results were correlated with the clinical findings and course. Results. Erosive pustular dermatosis of the scalp was observed in elderly patients with androgenetic alopecia and field cancerization of the capillitium; most patients had multiple comorbidities. Therapy used to treat actinic keratosis lesions (eg, imiquimod, ingenol mebutate), photodynamic therapy, cryotherapy, trauma, and surgery all were found to have predisposed for or led to EPDS. Erosive pustular dermatosis of the scalp presented clinically as exophytic crusts and pus overlying shiny granulation tissue. Histopathological findings demonstrated an ulcerated epidermis and dermal infiltrates dominated by lymphocytes together with a multitude of plasma cells. Plasma cells were found in all 21 biopsies and represented a common criterion for the correct diagnosis. The erosive lesions healed well within weeks after therapy with topical steroids. Conclusions. Chronic, poorly healing lesions with crusts and pus over shiny granulation tissue on the scalp are suggestive of EPDS, which should be confirmed by biopsy. Histological clues to a diagnosis of EPDS include dermal infiltrates of plasma cells and lymphocytes. The topical application of high-potency steroids showed great effectiveness in the present study.