A case of erosive pustular dermatosis of the scalp fairly well improved by topical application of corticosteroid

A 78-year-old female visited our clinic complaining of gradually expanding crust formation and hair loss lesion on her scalp over a few months. She had a history of rheumatoid arthritis, but had not taken anti-rheumatic agents for half a year. She had undergone an operation for gastric cancer five years previously and was still taking TS-1® (tegafur, gimeracil, oteracil potassium) for postoperative chemotherapy. At her first visit to our clinic, the parietal region was widely covered with a thick yellowish crust, from which pus was discharged from the periphery when pressed. This crust was easily removed from the surface along with blocks of hair to reveal erosion and shallow ulceration with hair loss. Staphylococcus aureus and coagulase-negative Staphylococcus were cultured from the pus, but the crust and removed hair were negative for fungal growth. The erosion was slightly improved by oral and topical antibiotics, but the erosion and underlying erythema remained. Histopathology of the re-epithelialized hair loss region showed epidermis atrophy, loss of hair follicles and perivascular infiltration of lymphocytes in the dermis. The patient was diagnosed with erosive pustular dermatosis of the scalp based on the characteristic clinical features. Four weeks after the start of topical application of Antebate® (betamethasone butyrate propionate) (lotion) on the erythema and erosion, the pustular formation ceased, the erythema disappeared and the erosion was almost re-epithelialized. After eight weeks of the steroid therapy, hair regrowth occurred in the re-epithelialized area. This case involved alopecia pityrodes; however, in regions where hair follicles remained, hair growth was thought to occur due to external steroids.