Acne Inversa (Hidradenitis Suppurativa): What It Is, Treatments, Causes and More

• Acne inversa (hidradentis suppurativa) is a chronic skin disease involving inflammation of the apocrine sweat glands. 
• The condition causes lumps beneath the skin, which can enlarge to form painful abscesses and sinus tracts.
• The exact causes are unknown, but smoking, obesity and genetics are known risk factors. 
• There is no cure for acne inversa, however there are treatment options that may relieve symptoms and reduce the frequency of flare-ups. 
• In severe cases, surgery is the most effective treatment option.

Acne inversa (hidradentis suppurativa) is a chronic and potentially severe skin disease. It occurs when apocrine glands become inflamed, causing lumps to form beneath the skin. These lumps can range in size from small peas to large marbles. They may enlarge to form abscesses which can be unsightly, painful to touch and foul smelling when they rupture. In some cases, they may also form sinus tracts and scarring.

Acne inversa can be challenging to treat and have an impact on quality of life. To date, there is no permanent cure. However, with early diagnosis and intervention, some patients can manage symptoms with over-the-counter (OTC) and prescription medications. Surgery is an option for severe cases and has relatively high success rates. Promising new treatment options are also in development.

Acne Inversa (Hidradenitis Suppurativa)

Although acne inversa manifests as pimples, lesions and bumps, it is not actually a type of acne. Rather, it is an inflammatory disease that affects the hair follicles around the sweat glands. 

The condition is estimated to effect between 1% and 4% of the population. It typically occurs after puberty, most often in the 20s or 30s, and rarely occurs in patients over 50 years old. Women are around three times more likely to develop acne inversa than men.

Symptoms

The symptoms of acne inversa include:

• Lumps, bumps or acne-like rashes
• Open or closed comedones
• Pustules
• Abscesses
• Body odor
• Itching 
• Excess sweating

Symptoms may present gradually and take months to develop. For some patients, the first warning sign is a single, inflamed bump on the skin. It may also be a small, series of bumps in the same general location.

These bumps may breakout repeatedly before eventually becoming infected. When bacterial infections occur, nodules or abscesses form beneath the skin. As well as being painful and itchy, these bumps omit a bad smell when they rupture. They tend to reoccur and, in severe cases, may cause scarring when they heal. 

If the lesions are deep, they can form sinus tracts or wound tunnels under the skin. These sinus tracts can become interconnected, leading to the entrapment of bacteria. This may worsen the condition by increasing infection and inflammation.

What areas are affected?

Hidradenitis suppurativa is known as acne inversa, because it affects the inverse areas of the body. The condition is most likely to show up around apocrine sweat glands where hair grows, including:

• Under the armpits
• Around the groin
• Beneath the buttocks
• Under the breasts

As well as the high concentration of sweat glands and/or hair follicles, skin tends to rub together in these regions which causes irritation.

Acne inversa may also occur on other areas of the body, including the waist and abdomen, although these cases are much less common. 

Stages of Hidradenitis Suppurativa

There are several systems used to classify patients with acne inversa. The Hurley clinical staging system is the most common.

According to the Hurley staging system, acne inversa can be classified into the following severity groups: 

• Stage I – recurrent abscesses without sinus tract formation or scarring.
• Stage II – recurrent abscesses (single or multiple separated lesions), with one or more sinus tracts separated by normal skin.
• Stage III – multiple interconnected sinus tracts without normal skin in between.

In Stage I, patients suffer mild inflammation and symptoms may be mistaken for acne. In Stage II, inflammation is more frequent and painful, and may restrict movement. In Stage III, lesions can enlarge to the point where patients are unable to function. 

What Causes Acne Inversa?

The exact causes of acne inversa are still unknown. However, doctors hypothesize that environmental and genetic factors may trigger the condition. The most commonly studied risk factors for developing acne inversa include:

• Smoking
• Obesity
• Family history

Smoking – In a study of 84 patients treated for acne inversa, 88.9% were cigarette smokers. As such, absolute cessation of smoking is recommended is conjunction with treatment.

Obesity – The prevalence of acne inversa is higher amongst obese people compared to the background population. A study found that weight loss of more than 15% can significantly reduce the severity of symptoms. 

Family history – Dermatology studies highlight the correlation between acne inversa and genetic factors, finding that between 30% and 40% of patients reported a family history. So, if have a relative with acne inversa, you may be more likely to get it.

While the causes of acne inversa are still being studied, experts agree the condition is not caused by poor hygiene, shaving, deodorants or creams. They also agree that acne inversa is not an infectious disease.

Is There a Cure?

Unfortunately, there is no permanent cure for acne inversa. However, the following treatment options may help control symptoms and reduce the frequency of flare-ups.

• Over-the-counter (OTC) medications
• Prescription medications
• Home remedies
• Surgery

Over-the-Counter Treatments for Acne Inversa

The following over-the-counter (OTC) treatments may provide some relief from mild symptoms of acne inversa.

• Acne cleansers
• Non-steroidal anti-inflammatory drugs
• Topical retinoids

Acne cleansers

Antimicrobial cleansers are sometimes recommended to reduce inflammation and dry out lesions. The most commonly used cleansers contain ingredient one or more of the following ingredients:

• Benzoyl peroxide – an organic acid with strong antibacterial properties
• Chlorhexidine – a broad spectrum disinfectant and antiseptic
• Hydrogen peroxide –  an oxidizing agent that kills bacteria and dries up skin

As for the effectiveness of acne cleansers, there is limited evidence to prove they work. However, that could be due to patient adherence. A study found that acne inversa patients were less likely to adhere to OTC treatments compared to prescription medications. They reported little benefit from using acne washes and often faced challenges obtaining them.

Non-steroidal anti-inflammatory drugs

Non-steroidal anti-inflammatory drugs (NSAIDs), such as aspirin, ibuprofen or naproxen, can ease pain and reduce swelling. While these medications may help with short-term discomfort, they do not treat the underlying disease. As NSAIDs have potential side effects, be sure to discuss the best options with your doctor or dermatologist.

Topical retinoids

Topical retinoids have been used for decades to treat a range of skin conditions. They have powerful anti-inflammatory properties that fight bacterial infections. They are available OTC (in mild strengths) in cream, lotion or gel formulas. Although the effects are modest, two particular types of retinoids, adapalene and tazarotene, have been proven to reduce inflammation associated with acne inversa. 

Prescription Treatments

Prescription medications are the first-line treatment for patients in Hurley Stage I and Stage II. The most popular prescription treatments include:

• Corticosteroids
• Antibiotics
• Oral retinoids
• Biologics

Corticosteroids

Corticosteroids are a class of drug that lower inflammation in the body. They may facilitate the healing of lesions, prevent future lesions from forming, and help with pain management. Corticosteroids are usually administered intravenously, directly into lesions. Injections can be repeated every 2-3 weeks. In some cases, they may be prescribed orally.

Evidence suggests the anti-inflammatory effects of corticosteroids may be most useful in acute cases. 

Antibiotics

Antibiotics are often prescribed to treat patients in Hurley Stage I or Stage II. They work by fighting infection and killing bacteria. The most commonly used antibiotics for acne inversa are clindamycin and tetracycline.

Clindamycin is a topical medication that is best suited to patients with localized symptoms and no deep, inflammatory lesions. A typical dosing regimen is twice daily for 3 months.

Tetracycline is an oral antibiotic that is recommended for patients with more widespread symptoms. It can be used for up to 4 months. 

Testing has shown no significant difference between these two antibiotics. Your doctor will determine the most suitable treatment based on individual symptoms.

Oral retinoids

Oral retinoids such as isotretinoin (Accutane) are typically used to treat acne. Because isotretinoin has anti-inflammatory properties and reduces bacteria in the hair follicles, it is also effective for acne inversa.

Isotretinoin treatment is proven to work for patients in Hurley Stage I or Stage II. In a recent study, 68% of patients showed partial or complete response to isotretinoin treatment.

Biologics

Biologics are powerful medications that can be developed from proteins, DNA, cells and all sorts of living organisms. They work by strengthening your body’s immune system and response to germs. These drugs are administered intravenously and are used to treat chronic inflammatory diseases such as arthritis. 

Adalimumab is currently the only US FDA-approved biologic for acne inversa, and it has been trialled with promising results. However, clinical trials are being undertaken into other biologics.

Treating Acne Inversa At Home

In addition to medications, there are some lifestyle habits and self-care practices to treat acne inversa at home. These include:

• Diet
• Warm compress
• Tea tree oil
• Turmeric
• Honey

Diet

As obesity is a known risk factor for acne inversa, a healthy diet is important to prevent and manage the disease. Research indicates that low-glycemic diet comprised of natural, whole foods and no dairy products may be the best approach. This type of diet may reduce the progression of lesions and prevent new lesions from forming, even when medications fail.

A Mediterranean diet can also be beneficial, as it is rich in anti-inflammatory foods that may prevent and reduce swelling. Foods known for their anti-inflammatory properties include:

• Oily fish, such as salmon, mackerel, tuna and sardines
• Nuts and seeds
• Tomatoes
• Green leafy vegetables
• Extra virgin olive oil
• Dark chocolate

Warm compress

For mild cases of acne inversa, a warm compress can reduce pain and discomfort. You can make a warm compress by running a clean washcloth under hot water and placing it on your skin for 10 minutes. You can also use a dry source of heat, like a heating pad.

Tea tree oil

Tea tree oil is a popular essential oil that has anti-inflammatory, antifungal, antiseptic and antimicrobial properties. It can help reduce swelling and inflammation. To avoid irritation, it’s important to dilute tea tree oil with a carrier oil, such as almond oil or coconut oil. Use 12 drops of carrier oil for every 1-2 drops of tea tree oil, then apply directly to skin. 

Turmeric

Turmeric has antibacterial, antioxidant and anti-inflammatory properties that make it useful for treating many medical conditions. For acne inversa, it may help reduce inflammation and ward off bacterial infections. To use, mix 1 tablespoon of turmeric with half a tablespoon of carrier oil, such as almond oil or coconut oil. Apply the mixture directly to skin and leave for 15 minutes.

Honey

Like turmeric, honey offers many healing health benefits. It has been used for centuries to treat a range of skin diseases. As well as having strong anti-inflammatory properties, honey is also an antibacterial which may prevent infection. Honey can be applied directly to the skin or added to the turmeric mixture above. Leave it on for 15 minutes before washing off.

Surgery for Hidradenitis Suppurativa

While medications and at-home treatments may reduce acne inversa symptoms, they rarely provide permanent relief. As such, surgical interventions are common for chronic and recurring cases. 

The main types of surgical procedures for acne inversa are:

• Radical surgical excision
• Skin tissue-saving excision with electrosurgical peeling (STEEP)
• Laser and light-based therapies

Radical surgical excision involves complete removal of lesions plus skin and fat around the affected area. Skin grafts are required and may take months to heal. As such, this treatment is only recommended for the most severe cases. Suitability for radical excision is determined on the size and location of lesions. 

In a study of patients who underwent radical surgical excision, around 60% reported a full recovery. A further 30% reported partial recovery after a 2 year period. 

STEEP involves unroofing abscesses and sinus tracts to excise affected tissue. Unlike radical excisions, which reach deep into the subcutaneous fat, the STEEP method spares surrounding tissue. This technique results in low recurrence rates, high patient satisfaction and relatively short healing times. 

In an open study of patients who underwent STEEP treatment, 83% reported no recurrence within 34 months post-surgery.

Laser and light-based therapies have become more commonly used to manage acne inversa. These treatments work by decreasing the number of hair follicles and bacteria in affected areas, and by debulking chronic lesions. Carbon dioxide laser surgery is the most common laser treatment for acne inversa. 

In a study of 58 patients who underwent this treatment, 95% reported some improvement or great improvement. However, 29% reported recurrence of lesions.

Takeaway

Acne inversa (hidradenitis suppurativa) is a severe skin disease characterized by painful, recurrent lumps around inverse areas of the body – most commonly under the armpits, around the groin and between the buttocks. These lumps can rupture and lead to sinus tracts and scarring.

Doctors are still unsure on the exact causes, but smoking, obesity and genetics are all known risk factors. Therefore, maintaining a healthy body weight and avoiding cigarette smoking are essential for prevention and management.

Unfortunately, there is no cure for the acne inversa, although OTC and prescription medications, as well as at-home remedies, may provide some relief. Surgery is also a treatment option for severe cases where quality of life is affected.
As acne inversa symptoms vary widely between individuals, it is best to talk to your doctor or dermatologist about tailoring a treatment plan. At any rate, early diagnosis and intervention is essential for best results.