Understanding Inverse Psoriasis

A type of psoriasis that exists where the skin folds

Psoriasis light and laser treatment
Light treatment for psoriasis.

Inverse psoriasis is often thought of as hidden psoriasis. This uncommon condition includes a rash that's similar to standard psoriasis—red and itchy—but in the case of inverse psoriasis, the rash doesn't appear on the exposed areas of your body. Instead, it occurs within your skin folds, such as the armpit and groin, and can produce debilitating pain and itching.

Symptoms and Causes of Inverse Psoriasis

Inverse psoriasis appears as a red rash that's tender and lacks the scales of standard psoriasis.

Itching and soreness might be particularly troublesome since the rash only presents itself in places where your body flexes or bends. Common areas of inverse psoriasis include your:

  • Groin
  • Armpits
  • Skin under your breasts
  • Folds around the genitals
  • Skin under the buttocks
  • In deep skin folds along your waist, stomach, and thighs

Perspiration and friction, which tends to gather in these areas, can make the condition and your symptoms worse.

It is possible to have inverse psoriasis without knowing you have typical psoriasis. If you have severe irritation and redness in your genital area, you could have inverse psoriasis, even if you have never been diagnosed with psoriasis. Any typical psoriasis you may have on another part of your body could be very mild and even passed off as simple dandruff.

Inverse psoriasis, which usually occurs in about 2 percent to 6 percent of those with psoriasis, is more bothersome and more typical in people who are overweight—although the connection between obesity and psoriasis has not been fully determined.

According to research, extra pounds won't cause you to develop psoriasis, but extra weight can increase the severity of your psoriasis.

Choose Inverse Psoriasis Treatment Carefully

Because inverse psoriasis occurs in some of the most sensitive areas of the body, treatment can be a challenge.

Topical medications used to treat inverse psoriasis range from over-the-counter hydrocortisone cream to prescription-strength medications, like Protopic (tacrolimus) and Elidel (pimecrolimus).

 Protopic and Elidel are preferred over cortisone-type treatments for inverse psoriasis because of your skin's sensitivity in these areas.

Some treatments, such as hydrocortisone, can cause skin thinning and other side effects. Do not take any medication without consulting your doctor first. If you experience troublesome side effects, call your doctor immediately. 

The U.S. Food and Drug Administration recommends that Protopic and Elidel only be used as a last resort and only for a short period of time because there's some evidence that they may increase the risk of certain cancers and viral infections.

Despite these strong warnings, The American Academy of Dermatology's official position is that it considers use of the medications under the supervision of a dermatologist to be safe and effective. Many dermatologists treating inverse psoriasis will use these medications first because they do not carry a risk of skin thinning.

UV Light to Treat Inverse Psoriasis

The use of ultraviolet B (UVB) type light is also helpful. Should your doctor prescribe this type of therapy, you would undress and stand in a specialized UVB light box. These appointments typically take place at your doctor's office.

The light is believed to slow the growth of psoriasis cells.

Although research is lacking, one case study reported that one patient achieved "complete clearance" of inverse psoriasis lesions after three weeks of UVB light treatment. A larger study involving the use of UVB light among those with standard psoriasis reported that about 66 percent were "90 percent clear after a maximum of 10 treatments."

Some people, usually those whose inverse psoriasis is worsened by moisture, find Castellani's Paint or Castederm helpful—a liquid medication, which contains the active ingredient phenol and comes in both prescription and nonprescription strength.

Domeboro astringent soaks, which are also available over the counter, may also be helpful.

If your inverse psoriasis is particularly stubborn, your doctor may recommend treatment with biologics such as Enbrel (etanercept) and Remicade (infliximab), which are taken via injection. 

Sources:

Gerber, W., B. Arheilger, T.A. Ha, J. Hermann, H.M. Ockenfels. "Ultraviolet B 308-nm Excimer Laser Treatment of Psoriasis: A New Phototherapeutic Approach." The British Journal of Dermatology. 149. 6. 1250-8.

National Psoriasis Foundation. Inverse Psoriasis fact sheet.

Luger, Thomas and Carle Paul. "Potential New Indications of Topical Calcineurin Inhibitors." Dermatology 215. Supplement 12007 45-54.

"Patient Information Sheet: Tacrolimus Ointment ." FDA.gov. Food and Drug Administration.

"Phototherapy: UVB Phototherapy." Psoriasis.org. National Psoriasis Foundation.

Van de Kerkhof , Peter. Textbook of Psoriasis . Second . Hoboken, NJ: Blackwell Publishing.

"What Psoriasis Looks Like." PsoriasisNet. American Academy of Dermatology.

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