Inverse Psoriasis (Flexural Psoriasis): Symptoms and Treatment

Medically Reviewed by Stephanie S. Gardner, MD on October 04, 2024
Written by Stephanie Watson, Kristen Fischer
9 min read

Inverse psoriasis is a condition that affects folds of skin. Skin cells multiply too quickly, and a rash forms in places like your armpits and groin where there is a lot of friction. Inverse psoriasis also known as flexural psoriasis, intertriginous psoriasis, and skinfold psoriasis.

How common is it?

Inverse psoriasis is a rare form of psoriasis. About 3% of Americans have psoriasis. Between 3% and 7% of those with psoriasis have inverse psoriasis.

Psoriasis vs. inverse psoriasis

Both psoriasis and inverse psoriasis are skin diseases. Psoriasis causes thick, scaly patches called plaques on the skin. Inverse psoriasis rashes aren't scaly like psoriasis plaques because they form in moist areas of skin. Many people with inverse psoriasis have plaque psoriasis, too.

An inverse psoriasis rash can look:

  • Red, purple, pink, or brown
  • Shiny or moist
  • Smooth and tight
  • Cracked

The color of the rash can vary, depending on your skin tone. For example, it may look purple or brown on dark skin and red on light skin. The rash may itch. Cracks called fissures can form in the creases of your skin, which may hurt and bleed.

Because of its location, inverse psoriasis may also cause:

  • Skin irritation from rubbing and sweating
  • Sexual problems because of discomfort
  • Yeast, fungal, and bacterial infections

Signs that an inverse psoriasis rash is infected include:

  • A bad smell
  • Bumps filled with pus
  • Swelling
  • Soreness

Where does inverse psoriasis usually show up?

Inverse psoriasis rashes form in places where you have skin folds and your skin rubs together, like:

  • Your armpits
  • Your groin
  • Your genitals
  • Between your buttocks
  • Under your breasts

The skin in these areas is more sensitive, so the condition is often a challenge to manage and treat. It can also be prone to infections, which can make the condition more complicated. 

Does inverse psoriasis have a smell?

On its own, inverse psoriasis doesn’t have an odor. But inverse psoriasis typically occurs in areas that can perspire. Bacteria and fungus can exist in those areas, so infections can occur there as well. If you have sweat in the skin folds or infections there, it may give off an odor. 

It can help to see photos of inverse or flexural psoriasis to see what you may be dealing with. Take a look at this picture to see how the condition looks and to see how it differs from other forms of psoriasis.

 

Here is how it looks in the creases of your arms. 

 

Doctors aren’t sure what causes psoriasis, but they know that genes and the immune system play major roles. Up to 40% of people with psoriasis have at least one close relative with the disease. Many of the genes linked to psoriasis help run your immune system.

When you have inverse psoriasis, a problem with your immune system causes too many new skin cells to grow. Those extra cells build up on your skin and form a rash.

Inverse psoriasis risk factors

In addition to your genes, these things can make you more likely to get psoriasis:

  • Smoking
  • Excess alcohol use
  • Obesity
  • Infections like strep

Certain things in your environment can set off flare-ups of inverse psoriasis. Possible triggers include:

  • Skin injuries like a cut or sunburn
  • Friction from the skin rubbing together
  • Medications like lithium and beta-blockers
  • Stress
  • Infections
  • Smoking
  • Drinking a lot of alcohol

Your doctor will ask about your symptoms and whether you have a family history of psoriasis. They'll also ask if you took any medications or had an infection right before your symptoms started. 

During the exam, your doctor will look for a rash in your skin folds and on other parts of your body. A special camera called a dermatoscope can magnify the rash so it's easier to see. The doctor may also check for nail changes and joint pain, which are other symptoms of psoriasis.

These tests may help your doctor diagnose inverse psoriasis:

  • Allergy tests to see if you have another type of rash called contact dermatitis
  • Skin tests
  • Blood tests to check for infections or other possible causes of your rash

Inverse psoriasis vs. jock itch

These two conditions both cause a rash in the groin area, but they are different.

Jock itch is a fungal infection that causes a rash in the crease between your thigh and groin. 

The rash gradually spreads to your upper thigh and butt in a ring or half-moon shape, sometimes with blisters at the edges. Your skin might be itchy, flaky, or scaly. You treat jock itch with antifungal medicine and by keeping the area clean and dry.

Inverse psoriasis also can show up in the crease between your thigh and groin, but it will be red, brown, pink, or purple and not scaly. And while inverse psoriasis is a chronic condition, jock itch is usually temporary and should clear up with antifungal treatment.

Inverse psoriasis vs. intertrigo

Intertrigo is a painful rash that happens when skin rubs together in places like the: 

  • Armpits
  • Neck
  • Breasts
  • Belly
  • Inner thighs
  • Butt
  • Spaces between the fingers and toes

Moisture builds up in these areas when you sweat, making your skin stick together and causing even more friction. Eventually, the skin can get damaged from rubbing together, creating cracks that allow bacteria to slip inside and cause an infection. Intertrigo is more common in people with obesity, diabetes, and in those who have a weakened immune system.

Many options are available. You can work with your doctor to find one that works best for you.

  • Corticosteroids. These medicines can come in forms called topicals that you put on your skin, like creams, lotions, oils, sprays, foams, gels, and ointments. They target the inflammation related to psoriasis. Doctors often prescribe them first. But be careful not to use too much of them, especially stronger ones. Overuse can lead to stretch marks or make the thin skin in these areas even thinner. Follow your doctor’s instructions. It’s also not a good idea to cover these areas with plastic bandages, since they trap moisture. If you have a yeast or fungal infection, your doctor may prescribe a medication to treat that, mixed with the corticosteroid.
  • Calcipotriene (Dovonex). This drug slows the growth of skin cells and reduces inflammation. It may make your skin sting or burn. If it does, talk to your doctor.
  • Pimecrolimus (Elidel) cream and tacrolimus (Protopic) ointment. The FDA approved these drugs to treat eczema, another skin condition. Some dermatologists say they work well for treating inverse psoriasis, too. But talk to your doctor before using them. The FDA warns people to use these medicines only for a short time because some studies suggest they may be linked to slight cancer risks.
  • Castellani's paint (Castederm). This product is "painted" onto your skin to dry the moist psoriasis lesions in skin folds. Doctors prescribe it when they think you also have a bacterial or fungal infection. If you need to keep moist areas dry, you can also try baby powder, baking soda, and zinc oxide powder.
  • Other topical medications. Treatments such as anthralin and coal tar can irritate skin folds. Your doctor may recommend diluting the creams with a moisturizer, or you can apply them for a short time and then wash them off. You can use these products alone or with a topical corticosteroid, but talk to your doctor about the best approach. Other creams include roflumilast (Zoryve), tapinarof (Vtama), and tazarotene (Tazorac), although the latter can be very irritating in sensitive skin fold areas.
  • Phototherapy. Ultraviolet (UV) light therapy works well for many types of psoriasis. Since inverse psoriasis affects areas that are hard to reach, you may need to go to the doctor's office to have this treatment.
  • Biologic medications. Biologic medicines are made from living cells and target specific parts of your immune system that play a role in psoriasis. You’ll get these drugs as a shot or an IV. Examples are:
  • Other medications you take by mouth. If you have severe inverse psoriasis, your doctor may recommend treatments that affect the whole body to ease your symptoms. You can take some of these drugs as a pill, such as acitretin (Soriatane), apremilast (Otezla), cyclosporine (Sandimmune), and methotrexate (Rheumatrex, Trexall).

Other treatments for inverse psoriasis

Diet and nutrition, exercise, mind-body techniques, and other treatments such as acupuncture can also be used to treat psoriasis triggers and maintain overall health. Your doctor may recommend these in addition to other treatments such as medications.

If you have inverse psoriasis, you may also be at higher risk of these conditions:

  • Type 2 diabetes
  • Heart disease
  • Heart attack and stroke
  • Obesity
  • High cholesterol

Your doctor might prescribe one of these medicines to treat inverse psoriasis:

  • Corticosteroid cream or ointment
  • Tacrolimus ointment or pimecrolimus cream
  • Vitamin D ointments like calcipotriol or calcitriol
  • Tar-based medicines 
  • Creams like roflumilast or tapinarof

Taking these medicines the way your doctor prescribed them will help clear up the rash.

You can also manage inverse psoriasis at home with these tips:

  • Gently wash between your skin folds and fully dry those areas.
  • Apply moisturizer to the rash.
  • Relieve stress with meditation, yoga, or other relaxation techniques.
  • Eat a Mediterranean-style diet to reduce inflammation and maintain an optimal weight.
  • Avoid injuries to your skin.

Inverse psoriasis is a skin condition that causes a rash in areas of friction, like the armpits and groin. A family history of obesity, excess alcohol use, or smoking can increase your risk of inverse psoriasis. Prescription creams or ointments clear up the rash. Losing weight and avoiding injuries to your skin will help prevent inverse psoriasis rashes in the future.

Is inverse psoriasis a fungal infection?

No. Psoriasis is an autoimmune disease that makes your skin cells multiply faster than usual. Sometimes, people mistake it for jock itch, which is a fungal infection, because both conditions can cause a rash in the groin area.

What can be mistaken for inverse psoriasis?

Many other conditions look similar to inverse psoriasis, including:

  • Intertrigo
  • Fungal infections like jock itch 
  • Bacterial infections like staph or strep
  • Skin conditions like seborrheic dermatitis, lichen planus, and contact dermatitis

How can I stop psoriasis from spreading?

Psoriasis isn't contagious, but it can pop up in different parts of your body if you have uncontrolled inflammation. You can stop it from spreading by avoiding triggers – like skin injuries, infections, smoking, alcohol, and stress – and by following the treatment plan your dermatologist prescribes. Controlling triggers can help ensure that your psoriasis stays as well controlled as possible.

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