What is psoriasis?
Psoriasis is a very common skin rash that affects up to 2% of the population. There are several different types but the usual form appears as silvery scaly patches over the elbows and knees. Other areas of the skin can be affected including the scalp and some people have changes in their nails. Psoriasis can occur on the genital skin as part of more general disease but in some people, it affects only this area.
What happens in psoriasis?
Skin cells are constantly being renewed and skin cells move up to the surface layers of the skin over a period of about 30 days. In psoriasis, this renewal is accelerated and only takes about 7 days. This leads to the skin being shed in large crusts or scales. Because the problem is inflammation, the skin will look red.
What causes it?
The cause of psoriasis is unknown. However, it is known that it can be triggered by some common throat infections in people who have particular genes. It can run in families but there is not always a family history. Stress can make the problem worse.
Psoriasis is NOT contagious. It is not related to hormonal changes, diet or any type of allergy. Genital psoriasis is not due to any sexually transmitted infection and is not contagious to sexual partners.
What does it feel like?
There may be no discomfort. Some itching may occur and at times this can be severe especially if the area gets infected with yeast (thrush) or bacteria. Splits or cracks in the skin can be painful and bleed.
What does it look like?
When psoriasis occurs on the skin it appears as dry patches with silvery scales. However, on vulvar skin (and in body folds elsewhere – the armpits, under the breasts, the groins), the surfaces are in a moist environment and so the dry scaling is not usually seen. Vulvar psoriasis appears as moist, salmon-pink patches which usually have a well-defined edge. It most commonly affects the outer labia and can spread to the groin folds and up on to the mons pubis.
How is it diagnosed?
Health care providers who are familiar with this condition will make the diagnosis by recognizing the typical appearance. If you have changes on the rest of the skin, this will often help to confirm the diagnosis.
How is it treated?
There is no cure for psoriasis, but it can be controlled with treatment. It may completely disappear but can recur and you may need to treat it from time to time.
Local care is important. It is vital to avoid irritants e.g. soaps, perfumes, sprays. Moisturising ointments (emollients) such as plain petrolatum or a barrier cream can be helpful. Wear loose clothing as this will help to reduce friction to the area. Avoid scratching or irritating the area as this will make psoriasis flare.
Steroid creams or ointments are very useful in treating psoriasis in the genital area. If the skin is splitting, it is common to find some superficial infection on the skin and so a combination treatment of a steroid together with an anti-candida (anti-thrush) or antibiotic component may be prescribed. Treating infection can help because infection makes psoriasis worse. Many of the treatments used to treat psoriasis elsewhere on the skin (coal tar, vitamin D creams, dithranol) are far too harsh to use on genital skin and can make things much worse.
Occasionally oral tablet treatments are used for severe psoriasis but these are rarely necessary for genital disease.
International Society for the Study of Vulvovaginal Disease
Patient Information Committee