Inverse psoriasis and intertrigo can both cause an itchy, inflamed rash in areas where the skin folds, such as the groin, armpit, and abdomen. However, these conditions have different causes and treatments.

People can easily confuse inverse psoriasis with intertrigo, as the symptoms and areas affected are similar.

However, inverse psoriasis is an autoimmune condition that will have flare-ups and periods of remission. Intertrigo, in contrast, occurs due to skin-on-skin friction and may resolve permanently with treatment and management.

This article explains what distinguishes these two conditions, including the differences between their causes, symptoms, and treatments.

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Inverse psoriasis, also known as intertriginous or flexural psoriasis, is a type of psoriasis that affects the body’s skin folds.

Between 3–7% of peopleTrusted Source with psoriasis experience inverse psoriasis, although they may underreport its prevalence.

Psoriasis is an autoimmune condition, which results from an immune reaction by a person’s body against their cells or tissues.

There is currently no cure for inverse psoriasis. This means that, although treatment can reduce and even eliminate its symptoms for a period, which doctors call remission, they eventually return.

Intertrigo is not an autoimmune condition. It is a skin disorder caused by skin-on-skin friction in moist and warm body areas.

Intertrigo may be acute, chronic, or relapsing. A person may be able to relieve symptoms permanently with treatment and management.

Several similarities and differences are present in the symptoms and body parts affected by the two conditions:

Inverse psoriasis

Inverse psoriasis causes inflammation and smooth patches on the skin, which become worse with sweat and friction. These skin patches are often moist and shiny.

On light skin tones, these patches may be bright red, whereas on skin of color, they may appear purple-ish or brown.

Inverse psoriasis typically affects the skin folds:

  • under the breasts
  • in the armpits
  • around the genitals and groin
  • between the buttocks

Intertrigo

Intertrigo mainly affectsTrusted Source the top layers of the skin in warm and moist body areas. It affects many of the same areas as inverse psoriasis.

Skin affected by intertrigo may be:

  • inflamed
  • discolored
  • uncomfortable
  • cracked and peeling if the area is moist
  • foul-smelling if a secondary bacterial infection is present

In inverse psoriasis, a person’s immune system triggers chronic inflammation. This inflammation causes the skin cells to grow too fast and build up on the skin’s surface.

This causes the smooth, shiny patches characteristic of the condition.

FrequentlyTrusted Source, Candida fungus or bacteria build up in the affected body areas.

Intertrigo is not related to the immune system. Instead, it occursTrusted Source due to the friction of skin folds against each other. Genetic factors may also play a role. Skin infections due to bacteria or fungi can contribute to the condition.

Doctors can diagnose inverse psoriasis and intertrigo by examining an individual’s skin and skin lesions. They may also perform one or more of the following tests:

  • Skin biopsy: This involves collecting a small sample of the person’s skin to examine under a microscope.
  • A KOH exam: This test checks if a fungus is causing the symptoms. A doctor scrapes a small portion of skin with a needle or blade and examines it under a microscope.
  • A wood lamp skin exam: A doctor looks at the affected skin area under UV light to check if a bacterium is causing the symptoms.

People who have overweight and those with deep skin folds have a higher risk of developing inverse psoriasis than others.

Individuals may also be more likely to develop inverse psoriasis if they have:

  • a family history of the condition
  • another form of psoriasis, such as plaque psoriasis

The followingTrusted Source are risk factors for developing intertrigo:

  • lack of mobility
  • having diabetes
  • obesity
  • living in a hot, humid environment
  • wearing splints, braces, artificial limbs, or other medical devices prone to become moist against the skin

To treat inverse psoriasis, doctors may prescribeTrusted Source the following treatments:

In some cases, a doctor may recommend using a biologic medication, such as ixekizumab (Taltz). These drugs affect the way the immune system works.

Treatment for intertrigo may depend on the underlying cause. Doctors may prescribe the following:

Lifestyle changes and home management

People may use lifestyle changes and home care to relieve the symptoms of both inverse psoriasis and intertrigo, including:

  • maintaining a moderate weight
  • frequently changing the body’s position
  • drying out moist areas of skin
  • drying and separating skin folds with dry towels
  • wearing loose clothing
  • regularly exercising, followed by thorough bathing and drying

Individuals may wish to talk with their doctor in the following circumstances:

  • more skin areas have become affected beyond the skin folds
  • the condition does not go away or gets worse with treatments and home care
  • they experience pain, discomfort, or difficulty performing daily activities
  • they experience problems in the joints, such as swelling or pain

Inverse psoriasis and intertrigo are two skin conditions that affect areas where the skin folds, such as the armpits and groin. This can cause discomfort and discoloration.

Although their symptoms are similar, inverse psoriasis and intertrigo are distinct conditions with different causes and treatments. Psoriasis is an autoimmune condition, while skin-on-skin friction causes intertrigo.

While there is no cure for inverse psoriasis, treatments can relieve or clear up a person’s symptoms. Doctors may prescribe treatments for intertrigo. Home management strategies may relieve symptoms for both conditions.