Inverse psoriasis is a form of psoriasis that occurs in areas where the skin folds. It is an immune-mediated inflammatory skin condition that causes itchy, scaly plaques to appear. It can occur in the armpits, under the breasts, groin, and genital region.

The location and appearance of these lesions tend to set inverse psoriasis apart from other types of psoriasis. People may find lesions occur in skin folds of the body, including, but not limited to, the groin, armpits, under the breasts, and the abdomen.

Inverse psoriasis affects 21–30% of people with psoriasis. It is also more common in people with deep skin folds.

This article explores the symptoms of inverse psoriasis and the similarities with other conditions. It also looks at treatments, causes, home care tips, prevention, and when to consult a doctor.

Inverse psoriasis may cause red lesions in the skin folds to appear smooth and shiny. Typically, people will find that the areas are itchy. They may also experience pain due to fissures or cracks that commonly form in the center of the plaques.

The lesions in the skin folds may present as well-defined dark brown or purplish patches in People of Color. An individual may also notice areas of darker or thicker skin.

Psoriasis is not contagious. Common areas affected by inverse psoriasis include the armpits, under the breasts, and groin. It can also occur in the genital area.

In the presence of warmth, moisture, and friction, the appearance of the skin changes and may further irritate inverse psoriasis.

People will often have other forms of psoriasis, such as plaque psoriasis. Plaque psoriasis is the most common type of psoriasis. Unlike inverse psoriasis, plaque psoriasis causes scaly plaques with thick overlying scales on other areas of the body, such as the elbows, scalp, and knees.

Diagnosis

A medical professional will typically diagnose psoriasis based on the appearance of the rash, the symptoms, personal medical history, and family medical history.

If the lesions occur in an area where the skin rubs against itself, the doctor may diagnose inverse psoriasis.

Doctors may also perform a skin biopsy to confirm the diagnosis and rule out possible fungal infection.

Learn more about psoriasis at our dedicated hub.

Complications

Inverse psoriasis, when left untreated, can lead to infection as well as other possible complications, such as:

  • chafing and irritation from heat and sweat
  • secondary fungal or yeast infections, particularly Candida albicans
  • lichenification or thickening of the skin from rubbing and scratching, particularly around the anus where fecal material irritates the area, causing increased itching
  • sexual difficulties because of embarrassment
  • thinned skin from the long-term overuse of strong topical steroid creams in the skin folds

Comorbidities

Several other conditions can occur with psoriasis.

These include:

Current guidelines suggest that doctors regularly check for these and other comorbidities if a person has moderate to severe psoriasis.

Similar to other types of psoriasis, the cause of inverse psoriasis may be multifactorial. There is more than one factor involved in developing psoriasis.

It may have a genetic component that triggers the immune system to become hyperactive, hence it is classified as an immune-mediated inflammatory disorder or an autoimmune disease. In psoriasis, this results in overproduction of skin cells as well as inflammation of other organ systems, usually the joints.

Psoriasis often flares from external factors, such as stress, or internal causes, such as an overactive immune system.

What causes a psoriasis flare-up in one person may not affect another.

Common triggers include:

  • severe stress
  • injuries, such as injections, sunburn, or a scratch
  • certain medications, including lithium and antimalarial tablets
  • infections that affect the immune system, especially strep infections or other common respiratory infections
  • sweating
  • excess weight that may result in larger skin folds

Research has not yet proven other possible triggers that may include allergies, diet, or even the weather.

Inverse psoriasis shares similar symptoms with other skin conditions. Below are some that doctors may often confuse.

Inverse psoriasis vs. jock itch

Both conditions tend to cause itchy, scaly patches in moist areas, such as the groin.

However, the rashes in inverse psoriasis can often appear shiny and smooth, while jock itch rashes are circular, half-moon rashes that peel, scale, or flake.

Jock itch is a scaly rash that often has a clearing in the center and a raised scaly border.

Infections can trigger flares of inverse psoriasis and often occur at the same time.

However, a fungus living on the skin called tinea cruris causes jock itch. Anything that gives the fungus a good environment to grow and multiply can trigger jock itch, including friction, heavy sweating, sharing of clothes and equipment, and moist skin.

Read more about inverse psoriasis and jock itch here.

Inverse psoriasis vs. intertrigo

Another rash that occurs in similar locations to inverse psoriasis is intertrigo. Intertrigo is an overgrowth of yeast, Candida albicans, on the skin and causes scaly, itchy, or tender patches where there is a moist environment.

Similar to inverse psoriasis, intertrigo affects the skin in warm, moist areas.

Intertrigo is more common in individuals who are:

  • diabetic
  • residing in hot and humid climates
  • confined to bed
  • elderly

Inverse psoriasis commonly affects people who are overweight and those with deep skin folds.

Read more about inverse psoriasis and intertrigo here.

Inverse psoriasis vs. superficial fungal infection

Superficial fungal infection can look like inverse psoriasis. However, a fungal infection usually has an annular, centrifugal, raised border with central clearing.

Symptoms also occur in dark and moist areas and affect various parts of the body. They do not occur in the armpits.

Similar to inverse psoriasis, treatments consist of topical antifungal agents, creams, and oral systemic medications.

In immunosuppressed individuals, this type of infection is quite severe and requires more potent antifungal agents.

Inverse psoriasis vs. Darier disease

Darier disease is a rare autosomal dominant genetic disorder. It typically presents with scaly, crusted, and raised areas on the scalp, upper chest, back, and skin folds.

The raised areas have a firm, harsh feel, similar to coarse sandpaper. If several areas grow together, they may form larger, wart-like lesions, which can have an unpleasant odor within skin folds. Unlike inverse psoriasis, Darier disease usually causes lesions that are the same color as a person’s skin.

It may also cause a heavily crusted rash similar to seborrheic dermatitis.

Inverse psoriasis vs. Hailey-Hailey disease

Another condition that can appear like inverse psoriasis is Hailey-Hailey disease.

Hailey-Hailey disease is a rare genetic disorder that causes blisters and erosions. It often affects the neck, armpits, skin folds, and genitals.

Unlike inverse psoriasis, which has well-defined patches, Hailey-Hailey disease lesions may develop a yellow crusty overlying layer. In many cases, the rash may cause an itching or burning sensation. The lesions may come and go and usually heal without scarring.

Similar to inverse psoriasis, sunlight, heat, sweating, and friction often aggravate Hailey-Hailey disease.

Treating inverse psoriasis can be difficult because it occurs in an area where the skin is thin and sensitive.

OTC topicals

Mild topical steroids are available over the counter (OTC), which can help reduce the redness and swelling.

The Food and Drug Administration has approved two ingredients to treat psoriasis. Products usually contain salicylic acid and coal tar. Other products may include aloe vera and zinc pyrithione, which help to moisturize, soothe, remove scales, or relieve itching.

The National Psoriasis Foundation (NPF) recommends keeping the lesions in skin folds dry. As skin folds increase the risk of infection, doctors usually mix topical creams with antifungal or anti-yeast medicines. Doctors will also recommend the use of powders to keep the area dry.

The NPF also recommends topical coal tar as second-line therapy in the treatment of inverse psoriasis, either on its own or in combination with topical steroids.

Read more about coal tar for psoriasis.

Prescription topicals

The most frequent treatment option for psoriasis is topical steroids. Corticosteroids control inflammatory responses and help reduce swelling and redness caused by plaques.

Doctors often prescribe topical steroids used short term to decrease inflammation.

Low-strength steroids are suitable for treating inverse psoriasis in the groin and under the breasts. However, doctors will recommend people use these with caution as the risk of side effects is greater in sensitive skin areas, where they can cause the skin to thin.

More commonly prescribed topicals that are safe to use in inverse psoriasis and in combination with steroids include:

Doctors will often prescribe antiseptics to try to prevent fungal or bacterial infections. Common prescriptions include chlorhexidine and chloroxylenol.

Other products also combine vitamin D with a corticosteroid. For example, Enstilar is a synthetic vitamin D3 analog and betamethasone mixed together, which helps reduce itch and inflammation.

Dovonex (calcipotriene) is also available as a vitamin D derivative.

Potential side effects of topical steroids include:

  • skin thinning
  • skin pigmentation changes
  • easy bruising
  • stretch marks
  • dilated surface blood vessels

Read more about how steroid creams treat psoriasis.

Systemic treatment

A systemic medication works throughout the body. People use these drugs for moderate to severe psoriasis or when topical medication and light therapy are ineffective.

Doctors prescribe this type of medication, and a person can administer it at home. Examples include methotrexate, cyclosporine, and mycophenolate mofetil.

These medications all suppress the immune system, and a doctor will monitor a person through regular blood tests.

Biologics

On the other hand, biologics are monoclonal antibodies that target a specific part of the immune system.

Depending on the biologic a doctor prescribes, a person can usually administer the treatment at home via self-injection.

If a person has a diagnosis of inverse psoriasis, a doctor may prescribe etanercept or infliximab as a biologic treatment.

Common side effects of biologics include an increased risk of infection due to the medication causing a decrease in a typical immune response.

Treatment with biologic agents, particularly tumor necrosis factor (TNF) alpha inhibitors, has an increased risk of tuberculosis (TB). Doctors will screen and treat latent TB infection in patients undergoing such treatment.

Demyelinating diseases, where the protective coating of nerve cells sustains damage, is a rare adverse effect of nonselective TNF inhibitors.

A person should speak with a doctor to discuss all possible risks, side effects, and benefits of biologics.

Read about other biologics that can treat psoriatic arthritis.

Hygiene and self-care can help manage the symptoms and improve the appearance of psoriatic patches.

Suitable home-care practices include:

  • taking only one bath or shower a day
  • regular bathing with lukewarm water
  • using a gentle, moisture-rich soap for sensitive skin
  • washing the skin very gently with the hands instead of a washcloth
  • rinsing off soap or cleanser gently
  • drying skin gently
  • applying fragrance-free moisturizer within 5 minutes of taking a shower or bath

Itching can be a problem for people with psoriasis. Several OTC anti-itch and cooling lotions are available to relieve these symptoms. Antihistamine drugs can also relieve itching.

Most people with psoriasis find that the sun helps to improve the appearance of their skin. However, due to the location of inverse psoriasis lesions, the sun will not help and may aggravate symptoms due to excess sweat.

Read more about the sun and psoriasis.

A person can take certain measures to help prevent flares of inverse psoriasis. These include:

  • using mild, fragrance-free antiperspirants, soaps, and body washes
  • reducing friction when exercising by wearing loose clothing
  • applying petroleum jelly or talcum powder to genital areas, armpits, or under the breasts to avoid irritation
  • washing sweaty areas, with a focus on the groin and genitals, with mild soap and water, and gently patting or blotting dry
  • keeping the environment cool to prevent excessive perspiration
  • avoiding certain foods that may be a trigger for psoriasis symptoms
  • avoiding stress, where possible
  • being aware of illnesses that may trigger flares

Read about other ways to prevent psoriasis flares.

Whenever there is a change in the skin, a doctor should evaluate it and treat it appropriately to reduce the risk of infection or other complications. People with psoriasis should see a doctor regularly as the condition causes systemic inflammation, such as cardiovascular issues.

The symptoms of psoriasis often resemble those of an infection. They require treatment, especially as lesions put the skin at higher risk of infection.

People who know they have psoriasis may not need to visit a doctor each time they have a flare, especially if they already have medication and are familiar with their condition.

However, if psoriasis gets worse, does not respond to current treatment, or there are signs of an infection, a person with psoriasis should see a doctor.

Inverse psoriasis can be difficult to treat in some cases, but certain lifestyle changes and topical medications can help control the symptoms.

It is important for people with inverse psoriasis to stay in touch with a doctor, especially if they have a flare-up that does not respond to prescribed medications.

It may also be helpful for people to avoid triggers that aggravate symptoms, such as certain foods or hygiene techniques.