Hidradenitis suppurativa

Hidradenitis suppurativa
Other names	Acne inversa, apocrine acne, Verneuil's disease, Velpeau's disease[1]
Hidradenitis suppurativa (Hurley's stage II) in the left armpit.
Specialty	Dermatology
Symptoms	Multiple inflamed and swollen skin lesions[2]
Usual onset	Childhood and Young adulthood[2]
Duration	Long-term[2]
Types	Stage I, II, III[1]
Causes	Unknown[3]
Diagnostic method	Based on symptoms[2]
Differential diagnosis	Acne, acne conglobata, pilonidal cysts[2]
Treatment	Warm baths, laser therapy, surgery[2][4]
Medication	Secukinumab, antibiotics, immunosuppressive medication[2]
Frequency	1–4% of people, when mild cases are included[2][3]
Deaths	Rare[1]

Hidradenitis suppurativa (HS), sometimes known as acne inversa or Verneuil's disease, is a long-term dermatological condition characterized by the occurrence of inflamed and swollen lumps.^[2][3] These are typically painful and break open, releasing fluid or pus.^[3] The areas most commonly affected are the underarms, under the breasts, perineum, buttocks, and the groin.^[1] Scar tissue remains after healing.^[1] HS may significantly limit many everyday activities, for instance, walking, hugging, moving, and sitting down. Sitting disability may occur in patients with lesions in sacral, gluteal, perineal, femoral, groin or genital regions; and prolonged periods of sitting down can also worsen the condition of the skin of these patients.^{[5][6][7][8][9]}

The exact cause is usually unclear, but believed to involve a combination of genetic and environmental factors.^[3] About a third of people with the disease have an affected family member.^[3] Other risk factors include obesity and smoking.^[3] The condition is not caused by an infection, poor hygiene, or the use of deodorant.^[3][4] Instead, it is believed to be caused by hair follicles being obstructed,^[10][1] with the nearby apocrine sweat glands being strongly implicated in this obstruction.^[1][11] The sweat glands themselves may or may not be inflamed.^[1] Diagnosis is based on the symptoms.^[2]

No cure is known,^[4] though surgical excision with wet-to-dry dressings, proper wound care, and warm baths or showering with a pulse-jet shower may be used in those with mild disease.^[4] Cutting open the lesions to allow them to drain does not result in significant benefit.^[2] While antibiotics are commonly used, evidence for their use is poor.^[4] Immunosuppressive medication may also be tried.^[2] In those with more severe disease, laser therapy or surgery to remove the affected skin may be viable.^[2] Rarely, a skin lesion may develop into skin cancer.^[3]

If mild cases of HS are included, then the estimate of its frequency is from 1–4% of the population.^[2][3] Women are three times more likely to be diagnosed with it than men.^[2] Onset is typically in young adulthood and may become less common after 50 years old.^[2] It was first described between 1833 and 1839 by French anatomist Alfred Velpeau.^[1][12]