What Is Intertriginous Psoriasis? Symptoms, Causes & Treatment

Smooth, glossy, red lesions in the folds of your body are typical features of intertriginous psoriasis. Because it occurs in moist areas of the body, it does not have the characteristic scaly patches of plaque psoriasis.

Intertriginous psoriasis generally appears as follows:

• Red, smooth, glossy skin lesions
• Absence of silvery scales
• Clearly defined lesions or occasionally extremely flat weeping plaques
• Skin irritation and discomfort

Since bacterial and fungal infections can cause similar symptoms, making an accurate diagnosis can be difficult. The expertise of a dermatologist can be helpful in detecting intertriginous psoriasis.

Experts are unclear what causes psoriasis or intertriginous psoriasis. However, all types of psoriasis are autoimmune diseases, which means that the immune system attacks healthy cells of the body. This promotes increased new skin cell formation and inflammation.

One major trigger of intertriginous psoriasis is irritation caused by friction and rubbing. Since the affected areas in the skin folds are warm and damp, they act as an ideal environment for bacteria, fungi, and yeast to grow, which activates the immune system even more. 

Other possible triggers of intertriginous psoriasis include:

• Stress
• Infections
• Injury or sunburn or scratch of the skin
• Alcohol and tobacco use
• Medications

People who are overweight or have deep skin folds are more likely to develop intertriginous psoriasis. It often affects people who already have another type of psoriasis, such as plaque psoriasis. 

Other risk factors that lead to intertriginous psoriasis include:

• Diabetes
• Compromised immune system
• Hot, humid environment
• Sweating
• Extreme stress
• Activities that cause chafing (rubbing and friction)

When left untreated, intertriginous psoriasis can cause infection and complications such as:

• Secondary fungal infection, most commonly Candida albicans (thrush)
• Skin thinning as a result of long-term use of powerful topical steroid creams
• Lichenification (a type of dermatitis) caused by rubbing and scratching
• Sexual problems due to pain and embarrassment

Because the condition is not fully understood, it is not always possible to prevent intertriginous psoriasis. However, you can take certain precautions to protect your skin, especially in areas that are more susceptible:

• Keep skin cool and dry
• Lose extra weight
• Use psoriasis medications
• Use fragrance-free, gentle cleansers
• Wear garments that are loose-fitting and made of absorbent materials

If you already have psoriasis, talk to your doctor about your risk of developing intertriginous psoriasis and how you can guard against the disease.

Treatment of intertriginous psoriasis usually involves topical ointments and creams. However, severe cases of intertriginous psoriasis are often treated with systemic medications. Both topical and systemic treatments may be prescribed if you develop any secondary fungal infections. 

Your doctor will discuss the appropriate treatment approach for you depending on the type and severity of your symptoms, as well as your medical history.

Topical treatments

• Zinc ointment: Zinc ointment is effective in treating mild cases of small, painless intertriginous plaques. 
• Calcipotriol ointment: Calcipotriol cream is a safe and effective treatment that should be administered twice daily. If it causes irritation, it can be applied once a day followed by hydrocortisone cream 12 hours later.
• Topical calcineurin inhibitors: Topical calcineurin inhibitors, such as tacrolimus ointment and pimecrolimus cream, may be effective in treating intertriginous psoriasis. Combinations of these therapies, as well as moisturizers, may be used.
• Antiseptics and topical antifungal medications:  Antiseptics and topical antifungal medications are frequently used because intertriginous psoriasis can be aggravated by bacteria and yeast, such as Candida albicans and Malassezia.
• Other topical agents: Treatments that are well tolerated in other skin areas, such as dithranol, salicylic acid, and coal tar, may cause irritation in skin folds. Therefore, these topical agents should be diluted with moisturizers before application on sensitive areas and washed off after a period of time. 

Systemic treatments

• Oral medications: Oral medications are tablets or capsules that are often used to treat severe cases of inverse psoriasis. These may include acitretin capsules, apremilast oral pills, and methotrexate tablets.
• Injections: Adalimumab, etanercept, and infliximab can be administered intravenously or under your skin to treat intertriginous psoriasis.

Phototherapy

In severe or chronic cases, ultraviolet B light treatment and biologic medications may be required. If you have a skin infection, your doctor will prescribe a topical antibacterial or antifungal drug.

Biologics

Biologics are monoclonal antibodies that specifically target a component of the immune system. Depending on the biologic prescribed, the treatment can typically be administered at home through self-injection. If you have intertriginous psoriasis, your doctor may prescribe etanercept or infliximab as a biologic therapy.

Biologics often cause an increased risk of infection, causing a decline in a regular immune response. The use of biologic medicines, notably tumor necrosis factor (TNF) alpha inhibitors, also increases the risk of tuberculosis. Therefore, if you are undergoing such therapy, your doctor will likely test for and treat latent tuberculosis infection. Demyelinating disorders, in which the protective covering of nerve cells is damaged, are rare side effects of nonselective TNF inhibitors.

Before using biologics, talk to your doctor about the potential benefits, risks, and side effects.