What are the other Names for this Condition? (Also known as/Synonyms)

• Acne Inversa
• Suppurative Hidradenitides
• Suppurative Hidradenitis

What is Hidradenitis Suppurativa? (Definition/Background Information)

• Hidradenitis Suppurativa is a chronic and longstanding skin condition that is characterized by recurrent boil-like lumps observed at locations where skins rub against each other, such as in the groin, buttocks, under creases of breasts, and the armpits
• The lumps or nodules (less than an inch in size), become inflamed and painful. These lumps break, and abscess formation occurs, oozing pus and fluid. The condition then heals; however, it causes significant skin scarring. The skin bumps may have smelly discharge due to infection
• Hidradenitis Suppurativa (also known as Acne Inversa) onset is during puberty, although the condition may remain misdiagnosed or undiagnosed for many years
• Both genetic and non-genetic factors are thought to contribute to the development of this chronic condition. Smoking, obesity, abnormal immune system, (and other factors) have been identified by researchers as being risk factors for Hidradenitis Suppurativa
• Though Hidradenitis Suppurativa is not a curable condition, treatment measures are available that include the use of topical creams and oral medications. Severe conditions may need surgical intervention

Hidradenitis Suppurativa can be divided into four subtypes:

• Axillary-Mammary-Inguinal Hidradenitis Suppurativa
• Follicular Hidradenitis Suppurativa
• Gluteal Hidradenitis Suppurativa
• Syndromic Hidradenitis Suppurativa

Who gets Hidradenitis Suppurativa? (Age and Sex Distribution)

• Studies indicate that Hidradenitis Suppurativa affects about 1 in 100 individuals (if the milder cases are also considered)
• Women are about 3-times more frequently likely to be affected than men. The cause of this discrepancy is unknown though
• The signs and symptoms of Hidradenitis Suppurativa can occur at any age, but it is most frequently observed to appear after puberty; with a peak incidence around the ages 15-25 years
• African American women are more prone to this condition than women belonging to any other racial or ethnic group

What are the Risk Factors for Hidradenitis Suppurativa? (Predisposing Factors)

Researchers have studied many possible risk factors for Hidradenitis Suppurativa. These include:

• Researchers have reported that obesity is associated with an increased severity of signs and symptoms in the affected individuals
• Smoking increases the risk for Hidradenitis Suppurativa
• A positive family history: Over 30% of the cases occurred in individuals having at least one family member with Hidradenitis Suppurativa
• A dysfunctional immune system, the lack of proper hygiene, or hormones seem to affect this skin condition and may play a vital role in its development
• The use of underarm deodorants, antiperspirants, hair removal agents, and shaving body hair do not seem to affect the development of this disorder
• Some patients with a genetic mutation in the PSTPIP1 gene have an increased risk for Syndromic Hidradenitis Suppurativa

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Hidradenitis Suppurativa? (Etiology)

Even though the exact cause of most cases of Hidradenitis Suppurativa (HS) is unknown, it is thought that environmental and genetic factors may play a causative role.

• The environmental factors include smoking and poor hygiene, while other factors are an abnormally functioning immune system, obesity, and hormonal conditions
• The specific gene associated with Hidradenitis Suppurativa has not been identified yet. Some studies have linked the disorder to chromosome 1; nevertheless, the exact location of the defect on chromosome 1 is unknown
• In case of a family history of the condition, it is important to note that some of the family members may have a milder form of the condition that may remain undiagnosed. In such cases, it has been reported that Hidradenitis Suppurativa can occur as an autosomal dominant pattern of inheritance
• In this skin condition, blockages of hair follicles occur in the affected areas. This is followed by increased inflammation that results in an abscess formation. Bacteria play a role in HS, but the disease is not a traditional infectious disease. The cause of blockage of hair follicles is unknown

What are the Signs and Symptoms of Hidradenitis Suppurativa?

Hidradenitis Suppurativa signs and symptoms manifest during the post-pubertal stage, i.e., into teenage and early adulthood. These include:

• The common locations of the recurrent boil-like lumps are the armpits and groin region (including the anus, buttocks, and to a lesser extent, the inner thighs)
• Other sites include the breasts (beneath the breasts mostly), nape of the neck, and waist
• The lumps or nodules, about 0.5-2.0 cm in size, become inflamed and painful
• Just as with acne, these lumps break, with the formation of abscesses, which then ooze foul-smelling pus and fluid
• When these ruptured boils heal, it causes significant scarring of the skin
• The bumps are painful and may burst, resulting in drainage of pus
• Some cases of Hidradenitis Suppurativa are mild, while others are very severe

The Hurley Staging System is used to assess disease severity in Hidradenitis Suppurativa:

• Stage 1 single or multiple nodules/abscesses, no sinus tracts or scarring, isolated lesions
• Stage 2 single or multiple nodules/abscesses, + sinus tracts or scarring, widely separated lesions
• Stage 3 multiple nodules/abscesses, + sinus tracts or scarring, diffuse/near diffuse involvement across the regional area with interconnected lesions

Syndromic Hidradenitis Suppurativa patients have several other severe inflammatory diseases coincident with HS. Note that in these Syndromes, Hidradenitis Suppurativa is abbreviated “SH” to make the acronyms clearer.

• PASH Syndrome is Pyoderma Gangrenosum, Acne Conglobata,   and HS
• PAPASH is Pyoderma Gangrenosum, Acne Conglobata, Pyogenic Arthritis, and HS
• PsAPASH is Psoriatic Arthritis, Acne Conglobata, Pyoderma Gangrenosum, and HS

How is Hidradenitis Suppurativa Diagnosed?

Hidradenitis Suppurativa may be diagnosed as follows:

• Physical exam with an evaluation of one’s medical history
• Blood tests
• Analysis of pus, and the culture of the fluid being drained
• Biopsy of skin lesions
• Imaging studies as required
• Differential diagnosis to eliminate other similar conditions must be considered

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Hidradenitis Suppurativa?

The complications of Hidradenitis Suppurativa could include the following:

• The presence of skin infections and scarred skin due to chronically-occurring nodules that ooze pus and form abscesses on the armpits, waist, neck, groin, and other regions can cause self-image issues, emotional and psychological problems, and even severe depression
• This could further lead to social and cultural ostracism and social isolation
• The nodules/bumps may rupture with drainage of pus. As the bumps heal, they may result in skin scars (fibrosis), leading to cosmetic issues
• The chronic pain may be debilitating
• The drainage of pus of infected areas may also cause squamous cell carcinoma of skin after many years

How is Hidradenitis Suppurativa Treated?

Hidradenitis Suppurativa (HS) cannot be cured; however, the symptoms are managed, and treatment is undertaken on a case-by-case basis.

• For mild skin conditions, self-care measures are recommended, such as washing with mild soap (antibacterial) and applying a warm compress
• For moderate skin conditions, topical applications and oral medications (such as antibiotics, retinoids, NSAIDs, and corticosteroids are first-line treatment 
• For more severe cases, the biologic modifiers adalimumab and secukinumab are FDA approved for Hidradenitis Suppurativa 
• For severe skin conditions with superficial to deep lesions, surgical interventions may be necessary. This might involve surgical incision and drainage of the lesions, which can ensure a quick healing process by removing skin and tissues that clog any tracts
• Chronic cases might require the removal of skin and reconstruction of the area using skin grafts
• A complete removal of the affected skin does not prevent the condition from recurring in other areas of the body. The recurrence may be aggravated by obesity and continuing skin infection
• To reduce discomfort and prevent the spread of infection, some of the suggestions include:
  • Avoid tight restrictive clothing; wear loose-fitting outfits
  • Keep the area clean
  • Use warm compresses to reduce inflammation
  • Avoid shaving hair
  • Laser hair removal in selected cases
  • Avoid smoking
  • Try not to gain excess weight
• For Syndromic HS, the other comorbid conditions must be treated simultaneously

How can Hidradenitis Suppurativa be Prevented?

• Currently, there are no specific methods or guidelines to prevent Hidradenitis Suppurativa, which is caused due to genetic and non-genetic factors
• Active research is currently being performed to explore the possibilities for treatment and prevention of Hidradenitis Suppurativa

What is the Prognosis of Hidradenitis Suppurativa? (Outcomes/Resolutions)

• Hidradenitis Suppurativa is a spontaneously developing and longstanding skin condition that may cause psychological and emotional trauma to the victims; particularly if the signs and symptoms are severe
• Both active and passive treatment measures are advocated to ensure an enhanced quality of life; however, Hidradenitis Suppurativa cannot be completely cured

Additional and Relevant Useful Information for Hidradenitis Suppurativa:

It is generally recommended to educate oneself about the condition and all aspects related to its management. Also, family and friends can help and support one in coping with Hidradenitis Suppurativa.

A more recent (2023) proposed classification system based on comorbid patterns, clinical characteristics, inflammatory and metabolic testing profiles, patient-reported outcomes, and treatment patterns identified six clinical subtypes of Hidradenitis Suppurativa. The potential utility of this more comprehensive system is yet to be determined.