From the dermatologikum hamburg: quiz.

A 78-year-old man presented with a keratotic and crusted plaque on the scalp (Figure 1). He had a history of multiple actinic keratoses with various attempts at treatment. The lesion was excised under the clinical diagnosis of squamous cell carcinoma. Photomicrographs of a section are presented in Figures 2A–S. What is your diagnosis? Erosive pustular dermatosis of the scalp The section pictured in Figure 2A–S shows an eroded and partly ulcerated epidermis (Figure 2G) covered by extensive scale crust housing numerous neutrophils (Figure 2S). Some neutrophils are scattered within the epidermis (Figures 2D and 2H). A diffuse infiltrate of neutrophils, lymphocytes, plasma cells, and histiocytes is present in the dermis (Figures 2i, 2A, 2Q). Fibrosis can be seen around infundibula of terminal hair follicles (Figures 2M, 2o). out of the clinical context, these findings are not unequivocally diagnostic and bacterial infection, deep mycosis, or dissecting cellulitis of the scalp may be considered in the differential diagnosis. in correlation with the clinical picture of a large crusted lesion on the scalp, however, the changes have to be interpreted as erosive pustular dermatosis of the scalp. in this patient, the lesions worsened after the surgical procedure (Figure 3A) and improved only with treatment with oral cor-ticosteroids (Figure 3B). Erosive pustular dermatosis of the scalp (EPDS) was first described by Pye and colleagues in 1979. They had observed six patients, all elderly women, who presented themselves with pustules and erosions on the scalp [1]. Lesions were not responsive to antibiotics but resolved on topical treatment with potent corticosteroids. Since 1979, a number of case reports and a few studies on patients with similar findings appeared in the literature of dermatology and have recently been reviewed [2]. Clinical descriptions of patients diagnosed with erosive pustular dermatosis of the scalp are very similar. Most patients were women presenting with crusts, pustules, and erosions on the scalp. in some patients, alopecia was said to have been accompanying. While many reports state that patients were elderly, a few reports told of patients less than 50 years of age. Lesions were said to have been present for months or years in most patients.