Hidradenitis suppurativa is generally seen in the areas having plenty of hair follicles and has many sweat glands (apocrine glands) like underarms, groin and anal area. It is also seen in the regions where there is friction between the skin like between the buttocks and beneath the breast.

The signs and symptoms of hidradenitis suppurativa are as follows. The disease has an insidious onset, where the first sign is erythema; later it becomes painful. Blackheads are commonly seen appearing in pairs also known as a ‘double-barreled pattern’. Red, painful bumps appear which are big in size and leak pus. The pus is foul smelling. Along with these bumps there is severe itching, burning and sweating. Painful, hard, pea-sized lumps form below the skin and may remain for years together. They may enlarge and become inflamed. The leaking lumps heal very slowly and if they heal they lead to scarring and form sinus below the skin. This draining represents persistent nodular hidradenitis suppurativa represented by intermittent discharge of pus and blood.

If left untreated, then over time many abscesses and sinus tracts develop a subcutaneous honeycomb. Ultimately fibrosis, scarring and induration develop. This condition usually begins after puberty presenting as a single painful lump for weeks or months.

Diagnosis is mainly done on the basis of clinical presentation but the following clinical tests may help in evaluation of the disease:

• Complete blood count: Helps in knowing any underlying disease like anemia, the erythrocyte sedimentation rate as well as the white blood cells count may be elevated in case of acute lesions. 
• Blood glucose levels should be done to find if the patient has underlying diabetes which tends to worsen the condition.
• Bacteriological analysis of the discharge should be done to identify the microorganisms in the lesions.
• Ultrasonography of the hair follicles can be done to find any abnormalities in the deeper parts of the follicle.
• CT scan or MRI can be done prior to the surgery to find out the exact extent of the disease.

Treatment depends on the presentation and extent of the disease. Following are the various approaches for the treatment of this condition:

Lifestyle

• Complete cessation of smoking.
• Reducing weight [22] and changes in food habits are essential to achieve the same. Wear loose clothes. Having hot baths with the mixture of distilled white vinegar and water helps [23].

Medicines

• Antibiotics: They help in controlling the disease and reducing the risk of future outbreaks. Antibiotics can be given orally or can be used in the form of ointments or creams for local application. Commonly used antibiotics are erythromycin, clindamycin, tetracycline, minocycline and metronidazole.
• Corticosteroids: Intralesional steroid injections can help in early resolution of the lesion. Orally high doses help in reducing inflammation.
• Tumor necrosis factor (TNF) alpha- inhibitors: Drugs like infliximab, adalimumab have shown promising effects in treatment of this condition but they increase the risk of infection, heart failure and few types of cancer.
• Anti-androgen therapy: Hormonal therapy showed beneficial effects with the use of cyproterone acetate and ethinyl estradiol, but the dosages are very high [24].
• Topical keratolytic agents like resorcinol has shown promising results in many cases due to its effect on follicular keratin plug [25].
• Zinc supplements also help in reducing inflammation and preventing new outbreaks.

Radiation

• Using x-rays in decreasing doses for temporary removal of hair from the root helps in treating this condition.
• Laser hair removal: Use of laser beams for permanent hair removal might aid in the treatment of hidradenitis suppurativa for long term.

Surgical

Surgical intervention becomes necessary in cases of chronic hidradenitis suppurativa. Nonsurgical intervention only supports the treatment but is important many a times before or after the surgery [22] [26] [27] [28]. Early diagnosis of the disease reduces the extent of surgery as well as prevents complications [27].

• Incision and drainage: When a single small area is involved, surgical drainage of that area should be considered, but this treatment gives only short term relief. 
• Exposing the sinus tracts: This process is also known as de-roofing; the skin and flesh are removed to uncover the underlying interconnected sinuses that link the separate lesions. The disease has chances of returning in the same area or another area in the body.
• Surgical removal: This involves wide surgical excision, with margins beyond the clinical borders of activity. Skin grafting may be needed for closure of the wound. 
• Surgical excision with the help of a carbon-dioxide laser and second-intention healing shows good results and has lesser complications. 
• Electrosurgery is the best alternative in treatment of hidradenitis suppurativa [29].

Recurrence after the surgery can occur if the excision was not done properly or if the apocrine glands are widespread [8] [27] [30].

Early extensive extraction has good results as it is followed by low recurrence rate [19]. If the disease is not diagnosed in time, and remains untreated, then it can lead to the development of squamous cell carcinoma in the anal and any other affected areas [20] [21].

The exact cause of hidradenitis suppurativa is unknown. Sometimes it is linked with autoimmune conditions [2]. As the disease is caused due to blockage and inflammation of hair follicles, there are various factors predisposing this condition like obesity [3], genetic factors [4], hormones [5], drugs and smoking.

Hidradenitis suppurativa affects 1% of the general population [6] [7]. Increased incidence is seen blacks as they have more number of apocrine glands as compared to whites [8]. It is considered to have predilection for females than in males, with ratio being 2-5:1 [9] [10] but this is controversial [9] [11] [12] as the comedones which are considered to be the precursor lesions for hidradenitis suppurativa are scattered equally in both the sexes and at all places [13].

The age of onset is between 11-50 years, [14] with an average patient age of 23 years [9]. But rarely it can occur before 11 years of age, [15] before puberty [16] and after menopause [17]. The prevalence amidst people older than 55 is much lower compared to younger people [18].

The exact pathogenesis of hidradenitis suppurativa is unclear. The anatomical distribution is suggestive of a disorder in apocrine glands. It begins with blocking of the apocrine or the follicular ducts due to keratinous plugging which in turn leads to ductal dilatation to balance the glandular component.

Infection begins via bacteria travelling through the hair follicle into the apocrine glands which are thereby trapped below the keratinous plug, and multiply rapidly in this
nutrient rich environment of the gland.

Ultimately the gland ruptures, causing inflammation that extends into the surrounding tissue and nearby glands. Bacterial infection with staphylococci and streptococci leads to added local
inflammation, tissue loss and skin damage.

Hidradenitis suppurativa cannot be prevented, but depending on the cause the disease can be controlled and flare ups can be avoided. Losing weight certainly helps obese people, even 10% reduction in the body weight can make a difference.

Avoid shaving the areas where the disease is active. Quitting the habit of smoking, wearing loose fitting clothes so as to prevent friction, helps in avoiding the flare-ups. Overheating and sweating can also lead to flaring of this condition, so try and keep your skin cool. You can even use an anti-perspirant to reduce sweating. If the condition is due to a bacterial infection then use antiseptic soaps or bath additives.

Hidradenitis suppurativa is a chronic skin condition affecting the apocrine gland-bearing skin and areas of friction like the armpits, groin, buttocks, inner thighs and beneath the breasts [1]. It is presented as comedone-like follicular blockage, long-standing relapsing inflammation, discharge containing mucous as well as pus leading to scarring.

Hidradenitis suppurativa is not a contagious disease. It occurs mainly after puberty but can affect any age group. It affects the areas of the body that are rich with sweat glands, hair follicles and are prone to friction like the underarms, groin, anal region, inner areas of thighs, between the buttocks and beneath the breast. It causes foul smelling mucopurulent discharge and often heals with scarring.

It is a very stubborn disease and is also a challenge for the physician to cure it completely. Sexuality of the person can also be affected due to the areas that are affected by this condition. People might also face challenges in their social circle because of the body odor and inappropriate treatment can lead to depression, frustration and isolation. As it is difficult to cure this disease, it is advisable that the patients take care of all the factors like weight, smoking, hygiene, clothes, sweating etc. to keep this condition under control.

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