Tight clothing, and clothing made of heavy, nonbreathable materials
Deodorants, depilation products, shaving of the affected area – their association with HS is still an ongoing debate among researchers. Drugs, in particular oral contraceptive pills and lithium. Hot and especially humid climates. Predisposing factors
Genetic factors: an autosomal dominant inheritance pattern has been proposed. Endocrine factors: sex hormones, especially an excess of androgens, are thought to be involved, although the apocrine glands are not sensitive to these hormones. Women often have outbreaks before their menstrual period and after pregnancy; HS severity usually decreases during pregnancy and after menopause.Some cases have been found to result from mutations in the NCSTN, PSEN1, or PSENEN genes. The genes produce proteins that are all components of a complex called gamma- (γ-) secretase. This complex cuts apart (cleaves) many different proteins, which is an important step in several chemical signaling pathways. One of these pathways, known as notch signaling, is essential for the normal maturation and division of hair follicle cells and other types of skin cells. Notch signaling is also involved in normal immune system function. Studies suggest that mutations in the NCSTN, PSEN1, or PSENEN gene impair notch signaling in hair follicles. Although little is known about the mechanism, abnormal notch signaling appears to promote the development of nodules and to lead to inflammation in the skin. In addition,  the composition of the intestinal microflora and as a consequence dietary patterns appear to play a role.
Hidradenitis suppurativa (HS), sometimes known as acne inversa or Verneuils disease, is a long-term dermatological condition characterized by the occurrence of inflamed and swollen lumps. These are typically painful and break open, releasing fluid or pus. The areas most commonly affected are the underarms, under the breasts, and the groin. Scar tissue remains after healing. 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 itself can also worsen the condition of the skin of these patients.The exact cause is usually unclear, but believed to involve a combination of genetic and environmental factors. About a third of people with the disease have an affected family member. Other risk factors include obesity and smoking. The condition is not caused by an infection, poor hygiene, or the use of deodorant. Instead, it is believed to be caused by hair follicles being obstructed, with the nearby apocrine sweat glands being strongly implicated in this obstruction. The sweat glands themselves may or may not be inflamed. Diagnosis is based on the symptoms.No cure is known. Warm baths may be tried in those with mild disease. Cutting open the lesions to allow them to drain does not result in significant benefit. While antibiotics are commonly used, evidence for their use is poor. Immunosuppressive medication may also be tried.