Retinoids and Psoriasis

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Introduction
Vitamin A, also known as retinol and its derivatives are essential for healthy normal skin growth. Retinoids are synthetic vitamin A derivatives and have been used for a number of years to treat conditions such as acne and photo-damage induced by the sun. They may be either taken orally or applied directly to the skin.

How do Retinoids Work?
Retinoid drugs work by binding to certain receptors in the skin cells. The early drugs developed were not very specific, so although they might have useful effects in a number of conditions like psoriasis, they also cause a range of side effects.

Retinoids work in psoriasis by:

  • Reducing the rate at which skin cells develop and renew themselves
  • Reducing inflammation

Oral Retinoids
Oral retinoids are useful treatments for patients with stubborn or severe psoriasis. However, patients may experience problems with dry skin and other side effects, which may require monitoring by the dermatologist. Retinoids should not be used by women of childbearing age due to their potential for causing abnormalities in an unborn child. Their use should also be avoided in patients with liver abnormalities.
The most common oral retinoid for treating psoriasis is Acitretin. Acitretin works well in combination with other treatments and is also an effective treatment for serious variants of psoriasis such as pustular and erythrodermic psoriasis. .

Emollients should be used to counteract dryness and irritation associated with oral treatments such as this. Any other side effects should be reported to your dermatologist.

Recent developments in retinoid therapy have resulted in a retinoid called tazarotene, specifically developed for topical psoriasis treatment.

Topical retinoids
In general, topical (applied to the skin) therapy is usually the first choice of doctors for the treatment of plaque psoriasis. Topical delivery, as well as targeting the lesions directly, also results in lower levels of absorption into the body and therefore fewer side effects than with oral drugs.

Tazarotene is special amongst the retinoids in that it bonds only the cell receptors in the epidermis responsible for the production of the abnormal psoriasis skin cells. As a result, there are no serious side effects experienced. Some people experience local irritation, which is usually mild to moderate in severity. The potential for irritation can be minimised by following some simple rules:

the gel should be applied thinly to the plaque only, in a circular motion. Start in the middle of the plaque and work outwards

Contact with the surrounding healthy skin should be avoided

If irritation occurs, the amount applied should be reduced until this initial reaction subsides.

Following clearance of the plaque, no further application is required and the effects of the treatment may be maintained for up to three months.