Dissecting cellulitis of scalp - Cellulitis
The condition typically affects African-American men between the ages of 20 and 40, but it can occur in other races, in women, and in children (it has been reported in girls). PCAS usually affects the vertex (although the entire scalp can be involved), producing boggy or fluctuant pustules and nodules. Patients complain of pain and of a disfiguring appearance. If one presses on a nodule, pus or serosanguineous fluid may extrude from one or more of the orifices. The disease may wax and wane over several years, later producing dermal fibrosis, sinus tracts, and hypertrophic scarring with alopecia. There is an increased risk of squamous cell carcinoma in patients with long-standing disease.
PCAS may occur alone or as part of a follicular occlusion triad that includes acne conglobata and hidradenitis suppurativa or a tetrad including pilonidal cysts.
PCAS has been rarely associated with skull osteomyelitis.
In contrast to classic cellulitis, dissecting cellulitis of the scalp demonstrates prominent nodularity. Lesions may be fluctuant and/or draining. Location and patient demographic factors, such as race, are important diagnostic clues.
L66.3 – Perifolliculitis capitis abscedens
77333008 – Dissecting cellulitis of scalp
Folliculitis decalvans – presents on the occipital and vertex scalp with erythematous follicular papules and pustules with scarring and yellow-gray scale surrounding the follicle. There may be erosions, hemorrhagic crust, and tufted hair. A skin biopsy may reveal deep perifollicular or intrafollicular mixed infiltrate of lymphocytes, histiocytes, or plasma cells without abscess or sinus tract formation.
Cellulitis or erysipelas – in contrast to classic cellulitis, dissecting cellulitis of the scalp demonstrates prominent nodularity.
Pseudopelade of Brocq
Ruptured epidermoid cysts
Fixed drug eruption
Erosive pustular dermatosis of the scalp