Painful lumps in the axilla
The location of these lesions and the odorous fluid that drained from them pointed to the diagnosis. The acne on the patient’s back was another clue.
Diagnosis: Hidradenitis suppurativa
The characteristic location and morphology of the lesions, along with the chronicity and odor, were critical in arriving at a diagnosis of hidradenitis suppurativa (HS).
HS is a chronic, inflammatory skin condition that normally manifests in areas of apocrine sweat glands, including the axilla, groin, and perianal, perineal, and inframammary locations.1 It begins when an abnormal hair follicle gets occluded and ruptures, spilling keratin and bacteria into the dermis. An inflammatory response can ensue with surrounding neutrophils and lymphocytes, which leads to abscess formation and destruction of the pilosebaceous unit. Sinus tracts form between the lesions, and a cycle of scarring, fistulas, and contractures can occur.
In this case, the comedones from acne conglobata on the patient’s back indicated a more global follicular occlusion disorder. The characteristic triad is hidradenitis suppurativa, acne conglobata, and dissecting cellulitis of the scalp—of which the patient had 2.
Other potential causes of the pathology include abnormal secretion of apocrine glands, abnormal antimicrobial peptides, deficient numbers of sebaceous glands, and abnormal invaginations of the epidermis.2 Increased levels of tumor necrosis factor alpha and other cytokines have been detected in HS lesions and are a potential target for therapy.
The prevalence of HS in the United States is approximately 0.1%.3 The condition typically begins between the ages of 18 and 39 years. The ratio of women to men affected by the condition is 3:1.2 There is no evident racial or ethnic predilection. There is an association with diabetes and Crohn disease.3 Obesity and smoking are risk factors.1
Continue to: The differential includes an array of common skin conditions
