Chronic Crusted Scalp Lesion of an Elderly Male

The document discusses the case of a 75-year-old man with a chronic crusted lesion on his scalp, diagnosed as Erosive Pustular Dermatosis of the Scalp (EPDS), a rare inflammatory condition that primarily affects elderly individuals. The lesion, which was nonhealing and had developed over six months following cryotherapy for actinic keratosis, was characterized by erythematous skin erosion with thick crusts and pustules, and was not responsive to antibiotics. A skin biopsy showed parakeratotic epidermis with lymphocytes and an inflammatory plasma cell infiltrate, and cultures for mycobacterial, viral, and fungal infections were negative. The lesion was successfully treated with a high-potency topical corticosteroid ointment, resulting in clearance within one month. The document also mentions that EPDS can be misdiagnosed as an infectious process due to its clinical appearance, leading to ineffective treatments. Other differential diagnoses for EPDS include tinea capitis, kerion celsi, actinic keratosis, squamous cell carcinoma, subcorneal pustular dermatosis, and pemphigus foliaceus. For cases where topical corticosteroids are ineffective, curettage followed by aminolevulinic acid photodynamic therapy (PDT) has been found to be a new effective treatment option.