Acne inversa or hidradenitis suppurativa (HS) is a disease that usually begins with pimple-like bumps on the skin. Pimples-like bumps tend to develop in places where everyday pimples do not appear. Acne inversa is most common on the underarms and groin. If acne inversa worsens, the pimple-like bumps can grow deep into the skin and become painful. Getting treatment for acne inversa is essential. Early diagnosis and treatment can prevent acne inversa from worsening.
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 improve 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 a lot like acne, folliculitis, or boils, it is best to see a dermatologist for a diagnosis.
- Deep acne-like cysts and blackheads
- Folliculitis (looks like swollen pimple with a hair in the center)
Signs and Symptoms of Acne Inversa
- Underarms (one or both)
- Groin (genitals, around the anus, and surrounding area)
- Upper thighs
- Women’s breasts (underneath and sometimes on the breasts)
Early signs and symptoms of Acne Inversa
- One (or several) breakouts that look like pimples or boils.
- Breakouts may stay on the skin; sometimes, they clear and reappear.
Later signs and symptoms of Acne Inversa
- Painful, deep breakouts that heal and reappear.
- Breakouts that rupture and leak a foul-smelling fluid.
- Scars that form as breakouts repeatedly heal and reappear.
- Scars become thicker with time.
- Skin begins to look spongy as tunnel-like tracts form deep in the skin.
- Serious infections.
- Skin cancer (rare).
The signs and symptoms of acne inversa can change quickly. Some people always have breakouts on their skin. One week, a person may have a foul-smelling fluid leaking from breakouts. The following week, the breakouts cleared, and scars were the only sign of acne inversa.
What is the differential diagnosis for acne inversa?
Differential diagnoses for acne inversa can include the following conditions.
- Staphylococcal skin infections, including abscesses, carbuncles, and furuncles.
- Cysts, like Bartholin cyst or epidermoid cyst.
- Cutaneous Crohn’s disease.
- Anogenital Crohn’s disease.
Acne Inversa and Skin Cancer Risk
acne inversa develops on skin that gets little or no direct sunlight. Most cases developed in men with long-standing HS on their genitals or around their anus. Yet, a few people have developed squamous cell carcinoma, a common type of skin cancer, where they had acne inversa breakouts and scarring for years.
What are the complications of acne inversa?
Complications of HS can include:
- Secondary infection
- Psychological effects and negative impact on quality of life
- Pyogenic granuloma
- Lymphoedema: female genital
- Squamous cell carcinoma: male anogenital
- Anemia of chronic disease.
Quality of life For Patients Who Suffers from Acne Inversa
Without treatment, acne inversa can continue its cycle of breakouts and healing. As the breakouts clear, scars form. Continual healing and scarring can cause hollow passages called fistulas to develop inside the body. Fistulas can be painful and require surgery to be repaired. People who have a foul-smelling liquid draining from the breakouts can feel embarrassed. They may feel too embarrassed to see a doctor. Dermatologists understand this. You should not feel ashamed to see a dermatologist about this problem.
Who gets Acne Inversa (Hidradenitis Suppurativa)?
Acne inversa often starts at puberty, is most active between the ages of 20 and 40, and can resolve at menopause in women. It is three times more common in females than in males. Associations and risk factors include:
- Family history of HS; 30–40% report at least one other family member affected
- Obesity and insulin resistance (metabolic syndrome)
- Cigarette smoking
- African ethnicity
- Follicular occlusion syndrome: acne conglobata, dissecting cellulitis, pilonidal sinus
- Inflammatory bowel disease, particularly Crohn’s disease
- Other skin disorders: psoriasis, acne, hirsutism
- Comorbidities: hypertension, diabetes mellitus, dyslipidemia, thyroid disorders, arthropathies, polycystic ovary syndrome, adverse cardiovascular outcomes
- Drugs: lithium, sirolimus, biologics
- PAPA syndrome
- PASH syndrome (pyoderma gangrenosum, acne, suppurative hidradenitis)
- PAPASH syndrome (pyogenic arthritis, pyoderma gangrenosum, acne, suppurative hidradenitis).
What causes Acne inversa (Hidradenitis Suppurativa)?
No one knows for sure what causes acne inversa. Because it occurs after puberty, hormones play a role. The person’s immune system also plays a role. Acne inversa may develop when a person’s immune system overreacts.
Acne inversa begins in the hair follicles (where hair grows out of the skin). Like common acne, acne inversa forms when the hair follicles clog with bacteria and other substances. Acne inversa may develop in people who have an immune system that overreacts to the plugged hair follicle. Lifestyle also plays a role. Smoking, being overweight, or taking lithium may trigger HS. These things do not cause acne inversa. If a person is susceptible to getting acne inversa, any of these could make HS appear for the first time or worsen existing HS.
Although ‘hidradenitis’ implies an inflammatory disease of the sweat glands, we know that HS is an autoinflammatory syndrome. The exact pathogenesis is not yet understood. Factors involved in the development of acne inversa include:
- Follicular occlusion
- An abnormal cutaneous or follicular microbiome
- Release of pro-inflammatory cytokines
- Inflammation causes rupture of the follicular wall, destroying sebaceous and apocrine glands and ducts.
How do Dermatologists Diagnose Acne Inversa (Hidradenitis Suppurativa)?
A dermatologist looks closely at the skin and asks some questions to diagnose this skin disease. If your breakouts are leaking fluid, your dermatologist may swab a bit of the liquid onto a slide to determine if you have an infection. You also may need a blood test.
What are the clinical features of acne inversa?
Acne inversa can affect single or multiple areas in the axillae, neck, inframammary fold, and inner upper thighs. Anogenital involvement most commonly affects the groin, mons pubis, vulva, scrotum, perineum, buttocks, and perianal folds.
HS is characterized clinically by:
- Open double-headed comedones
- Painful firm papules and nodules
- Pustules, fluctuant pseudocysts, and abscesses
- Draining sinuses linking inflammatory lesions
- Hypertrophic and atrophic scars.
How is the severity of acne inversa assessed?
Disease severity and extent are measured by clinical and ultrasound assessment at diagnosis and when monitoring response to treatment. There are several severity scales for HS [see guidelines for Acne inversa: severity assessment].
The Hurley system, the most widely used assessment tool, describes three clinical stages.
- Stage I: solitary or multiple isolated abscess formation without sinus tracts or scarring.
- Stage II: Recurrent abscesses, single or multiple widely spaced lesions, sinus tract formation.
Stage III: Diffuse involvement of an area with multiple interconnected sinus tracts and abscesses
How do Dermatologists Treat Acne Inversa (Hidradenitis Suppurativa or HS)?
The aim of acne inversa treatment is
- Clear or reduce breakouts.
- Get rid of scars and tunnels beneath the skin.
- Prevent new breakouts.
- Antibiotics: This is often part of the treatment plan. These drugs can reduce inflammation, fight infection, prevent HS from worsening, and stop new breakouts.
- Acne washes and medicines: Acne treatments that you can buy without a prescription may be helpful. Using these products alone usually will not clear HS.
- Bleach baths: If certain bacteria colonize (found on the surface of your skin), your dermatologist may recommend taking 5- or 10-minute bleach baths. You’d take this bath in your bathtub at home. If a bleach bath is suitable for you, your dermatologist will tell you how to make one.
- Biologics: These work on the immune system. Some, such as adalimumab, you inject yourself. Others require an infusion at a hospital or clinic. Some patients have seen the long-term clearing of their HS with a biologic. Due to possible serious side effects, you should discuss the risks and benefits with your dermatologist.
- Corticosteroid injection into a breakout: Your dermatologist may inject this into a painful cyst to reduce pain and swelling.
- Corticosteroid pills: This medicine reduces inflammation, which can help clear HS and prevent new breakouts.
- Diabetes drug: Metformin has been approved to treat adult-onset diabetes. It may also help people who have HS and metabolic syndrome.
- Hormone therapy: Some women relieve by taking birth-control pills, spironolactone. These medicines can decrease pain and the amount of fluid draining from the breakouts.
- Methotrexate (severe HS only): This medicine treats cancer and other medical conditions, such as severe psoriasis. It works on the immune system and may help control HS in some patients.
- Oral retinoid: A few patients with HS are helped.
- Radiation therapy: This treatment exposes the body to radiation, used less often today than before. Be sure to talk with your dermatologist about the short- and long-term risks to your body. Some patients have seen their HS clear.
- Wound dressings: If the HS causes tunnels beneath your skin, you will need to treat these as you would wounds.
Surgical treatment for Acne Inversa (Hidradenitis Suppurativa)
When HS grows deep into the skin, medicine alone may not be valid. Your dermatologist may recommend a surgical procedure. I can do the following in a dermatologist’s office or clinic:
- Laser surgery: This treatment shows promise. Some patients clear after several treatments. Lasers are proving effective at clearing new and deep HS breakouts. This treatment may be helpful because it destroys the hair follicles.
- Deroofing: This surgery may be an option for patients with painful HS that repeatedly return. The surgeon turns deep, painful HS into scars.
- Drain or incise: The dermatologist drains 1 or 2 lesions during the surgery or cuts them out. This can bring short-term relief, but the HS can return.
- Excision: This involves surgically cutting out the HS and some normal-looking skin. Because the wound is deep, the area needs to be covered with a skin graft (skin removed from another part of your body) or a skin flap (skin from nearby is pulled over to cover the wound). HS does not return to the treated area, but it can develop nearby.
No treatment works for everyone who has HS. Sometimes, a patient needs to try a few different medicines to find one that works.