Hidradenitis Suppurativa

1 What is Hidradenitis Suppurativa?

Hidradenitis Suppurativa, also known as acne inversa is a disorder that begins as pimple like lesions on skin. They develop at unusual sites, i.e. sites that are not common for acne like underarms, groin. Getting treatment for HS is important. Early diagnosis and treatment can prevent HS from worsening.

If HS worsens, the pimple-like lesions can grow deep into the skin and become painful. They can rupture, leaking bloodstained pus onto clothing. This fluid often has a foul odor.

As the deep bumps heal, scars can form. Some people develop tunnel-like tracts under their skin. As the skin continues to heal and scar, the scars thicken. When thick scars form in the underarm, moving the arm can be difficult. Thick scars in the groin area can make walking difficult.

Because HS can look lot like acne, folliculitis, or boils, it is best to see a dermatologist for a diagnosis. To a dermatologist’s trained eye, the differences between HS and other skin diseases are subtle but obvious. Proper treatment depends on an accurate diagnosis.

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2 Symptoms

Hidradenitis Suppurativa has several signs and symptoms

Hidradenitis can affect a single or multiple areas in:

  • the armpits,
  • neck,
  • submammary area,
  • and inner thighs.

Anogenital involvement most commonly affects:

  • the groin,
  • mons pubis,
  • vulva (in females),
  • sides of the scrotum (in males),
  • perineum,
  • buttocks and perianal folds.

Signs include:

  • Open and closed comedones
  • Painful firm papules and larger nodules
  • Pustules, fluctuant pseudocysts and abscesses
  • Pyogenic granulomas
  • Draining sinuses linking inflammatory lesions
  • Hypertrophic and atrophic scars
  • Many patients with hidradenitis suppurativa also suffer from other skin disorders, including acne, hirsutism and psoriasis.

The Hurley system describes three distinct clinical stages which are used to access the severity of the disease and impact of treatment:

  • Solitary or multiple, isolated abscess formation without scarring or sinus tracts
  • Recurrent abscesses, single or multiple widely separated lesions, with sinus tract formation
  • Diffuse or broad involvement, with multiple interconnected sinus tracts and abscesses.

Severe hidradenitis (Hurley Stage 3) has been associated with:

  •  Male gender
  • Axillary and perianal involvement
  • Obesity
  • Smoking
  • Disease duration

3 Causes

The following factors have been suggested as possible causes of hidradenitis suppurativa although exact reasons are not known exactly:

  • Post-pubescent individuals are more likely to exhibit HS.
  • Plugged apocrine (sweat) gland or hair follicle
  • Excessive sweating
  • Sometimes linked with other autoimmune conditions
  • Androgen dysfunction
  • Genetic disorders that alter cell structure
  • Patients with more advanced cases may find exercise intolerably painful, which may increase the rate of obesity among sufferers.

There are several triggering factors that should be taken into consideration

  • Obesity is an exacerbating rather than a triggering factor, through mechanical irritation, occlusion, and maceration.
  • Tight clothing and clothing made of heavy, non-breathable materials.
  • Deodorants, depilation products, shaving of the affected area – their association with hidradenitis suppurativa are still an ongoing debate amongst researchers. Drugs, in particular oral contraceptives and lithium.
  • Hot and especially humid climates.

4 Making a Diagnosis

A diagnosis of hidradenitis suppurativa is made based upon symptoms, medical history, examination and blood tests.

If pus or fluid drainage is present, a sample of fluid may be sent for a culture test in order to rule out other skin conditions. Clinical Testing and Work-Up:

Ultrasonography of hair follicles and the thickness of the skin can reveal abnormalities and show how the disease is progressing.

Other tests that have been used in evaluating the stage of the disease are C-reactive protein assay, urinalysis, serum IL-2 receptor levels assessment of the erythrocyte sedimentation rate, and a CBC count with differential and platelet counts.

5 Treatment

Since the cause for HS is multifactorial, there is no single treatment that will be effective for everyone.

General Measures

  • Weight loss.
  • Smoking cessation.
  • Loose fitting clothing.
  • Using anti-persipirants.
  • Daily wash with anti-septic soaps.
  • Simple dressings to draining sinuses.
  • Analgesics for pain control.

Medical Management

Treatment is often required for prolonged period. Various medications used are:

Antibiotics: Topical clindamycin, with benzoyl peroxide to reduce bacterial resistance

  • Short course of oral antibiotics for acute staphylococcal abscesses, eg flucloxacillin
  • Prolonged courses (minimum 3 months) of tetracycline, metronidazole, cotrimoxazole, fluoroquinolones or dapsone for their anti-inflammatory action
  • Six-to-twelve week courses of the combination of clindamycin (or doxycycline) and rifampicin for severe disease


  • Long-term oral contraceptive pill; antiandrogenic progesterones drospirenone or cyproterone acetate.
  • Spironolactone and finasteride
  • Response takes 6 months or longer.

Immunomodulatory treatments for severe disease:

  • Intralesional corticosteroids into nodules
  • Systemic corticosteroids short-term for flares
  • Methotrexate, ciclosporin, and azathioprine
  • TNFα inhibitors adalimumab and infliximab, used in higher dose, are the most successful treatments to date.

Other medical treatments:

  • Metformin in patients with insulin resistance
  • Acitretin (unsuitable for females of childbearing potential)
  • Isotretinoin – more effective for acne
  • Colchicine

Surgical management of hidradenitis suppurativa:

  • Incision and drainage of acute abscesses
  • Curettage and deroofing of nodules, abscesses and sinuses
  • Laser ablation of nodules, abscesses and sinuses
  • Wide local excision of persistent nodules
  • Radical excisional surgery of entire affected area
  • Laser hair removal

6 Prevention

Prevention of hidradenitis suppurativa (HS) is related to the possible causes of HS.

For example, bacteria seem to be involved in HS. For this reason, you may be able to prevent symptoms by washing your skin with antiseptic soaps or using bath additives.

HS appears in areas where rubbing often happens, such as under the breasts or on the insides of the thighs. You can help prevent rubbing by wearing loose fitting clothing and avoiding clothes that are too tight.

Smoking seems to make HS worse. If you smoke, you can help prevent HS symptoms by quitting. Talk to your health care provider about methods to help you quit.

To address the emotional symptoms of HS, you can seek help from other people living with the condition. Talk to your health care provider about support groups in your area.

HS is more common in people who are severely overweight. If you are at-risk for obesity or are obese, losing weight may help improve the symptoms of HS. Talk to your health care provider about weight loss programs or treatment. 

7 Lifestyle and Coping

Lifestyle modifications are necessary in order to cope with hidradenitis suppurativa.

The following suggestions may help relieve discomfort, speed healing and prevent the infection from spreading:

  • A warm washcloth or compress can help reduce swelling.
  • Gently wash the affected areas with antibacterial soap. After washing, apply an over-the-counter antibiotic.
  • Loose clothes and underwear can help prevent skin irritation, while tight, synthetic clothes may irritate your skin.
  • Excess weight increases the number of areas where skin rubs together — for example, between skin folds — causing friction, increased perspiration and bacterial growth. Though weight loss won't cure the disease, it may improve symptoms.
  • Use of Zinc has also been implicated of potential benefit.
  • Changes in diet avoiding inflammatory foods.
  • Warm compresses with distilled vinegar water, and taking hot baths with distilled white vinegar in the water, hydrotherapy, balneotherapy.
  • Icing the inflamed area daily until pain reduction is noticed.

8 Risks and Complications

Potential complications of hidradenitis suppurativa include:

  • Dermal contraction
  • Local or systemic infection resulting from the spread of microorganisms
  • Arthritis secondary to inflammatory injury
  • Squamous cell carcinoma (in indolent sinus tracts)
  • Disseminated infection (rare) 
  • Restricted limb mobility from scarring
  • Lymphedema caused by lymphatic injury from inflammation and scarring
  • Rectal or urethral fistulas
  • Systemic amyloidosis
  • Anemia from chronic infection.

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