DISCUSSION
In the US, hidradenitis suppurativa (HS) affects 1% to 4% of the population and about 4 times as many females as males. But as this case demonstrates, it is consistently misidentified as “boils” or “staph infection” by providers unfamiliar with the correct diagnosis.
HS involves hair follicles in intertriginous areas of the body that are rich with apocrine glands (eg, armpit, groin). The condition, initially known as acne inversa, was first described in 1833 by Dr. Alfred Velpeau, a French surgeon. Despite some minor similarities, HS is not actually a form of acne, nor is it an infection. About one-third of HS patients inherit the condition, and generally, onset occurs post puberty, suggesting a hormonal component.
With HS, the hair follicle and associated apocrine gland fail to function normally. As sweat accumulates in subcutaneous tissue, it creates a chronic inflammatory reaction manifesting with large comedones, cysts, and abscesses. Eventually, it can result in ropy, hypertrophic scars on the surface and deep tracts connecting multiple lesions. HS is classified as mild (stage 1), moderate (stage 2), or severe (stage 3) using the Hurley staging system.
HS is notoriously difficult to cure, but the anti-inflammatory effects of some antibiotics (eg, minocycline, doxycycline) can offer some relief, as can anti-androgens (eg, spironolactone). The use of isotretinoin has yielded disappointing results. For small lesions, intralesional injection of glucocorticoids can be useful for short-term relief of pain and swelling.
The most encouraging recent development in HS treatment is the approval for the use of adalimumab (Humira) in severe cases that have failed to respond to other modalities. Even with use of this biologic, decent control is probably the best outcome—and that’s at an annual cost of $50,000, plus the patient’s exposure to potentially serious adverse effects due to immunosuppression.
Another approach is surgical, with all its attendant risks, as this patient experienced in her right axilla. Simple incision and drainage offer little beyond temporary relief of pain.
Environmental factors should not be overlooked; obesity and smoking have both been linked to HS in multiple studies.
TAKE-HOME LEARNING POINTS
- Hidradenitis suppurativa, also known as acne inversa, results from malfunction of the hair follicle and associated apocrine glands in intertriginous areas.
- HS can range from mild (with minor pustules and sparse comedones) to and severe (diffuse disease, affecting multiple areas with heavy ropy scarring, large painful abscesses, and connecting tracts).
- HS affects approximately 4 times as many females as males, almost all with post-pubertal onset—strongly suggestive of a hormonal component.
- Treatment is problematic, although the recent approval of adalimumab for use in HS is proving to be helpful, if not curative. Some oral antibiotics and anti-androgens have shown mixed results.