Dissecting Cellulitis of the Scalp

For the past 7 years, a 32-year-old African American man had multiple nonpruritic scalp abscesses. He also reported intermittent fever and joint pain. The abscesses had been drained on many occasions, and he had received several antibiotics, although no organisms had been isolated. Collagen vascular disease, SAPHO syndrome (synovitis, acne, pustulosis, hyperostosis, osteitis), discoid lupus, and cutaneous sarcoid had been ruled out. During the past 7 years, he had been treated with prednisone, methotrexate, and hydroxychloroquine without any response.

Fungal cultures were negative for tinea capitis, and no nuchal lymph nodes were palpable.¹ Folliculotropic mycosis fungoides with large-cell transformation² was unlikely because the patient did not have any other systemic symptoms. Fluid from incision and abscess drainage revealed abundant neutrophils and red blood cells with no evidence of malignancy. Cultures and stains were negative for bacterial and fungal infection. The diagnosis of exclusion was dissecting cellulitis of the scalp.

The differential diagnosis of this condition includes acne keloid,³ which is associated with chronic, scarring folliculitis that affects mostly African American patients and is located on the back of the neck of young adults. The course is progressive and leads to hypertrophic scarring, chronic abscesses, and hair loss. Pseudopelade of Brocq,⁴ characterized by its lack of atrophy and "footprints in the snow" alopecia morphology, is another condition in the differential that generally occurs in white patients.

Dissecting cellulitis is difficult to treat. Medical therapies include antibiotic soap (chlorhexidine and benzoyl peroxide), dapsone, intralesional triamcinolone, zinc supplements, topical and oral isotretinoin, oral antibiotics (tetracycline and doxycycline), and oral corticosteroids. Simple incision and drainage and wide excision with split-thickness skin grafting have been used to treat severe cases when medical therapy has failed.