Le Psoriasis is a chronic disease that cannot be cured, so you can never be sure that flare-ups will never come back. Nevertheless, it is possible to relieve the symptoms effectively using drug products applied to lesions. The goal is to reduce the extent of the plaques and the frequency of relapses, but it is difficult to achieve their total disappearance. It may be necessary to try several treatments before finding one that works. It is also important to be regular in the application of treatments and to follow the doctor’s instructions, even if this is restrictive, if one wants to obtain good results.

The treatment is mainly based on the application of creams and D’ointments on the plates. In some cases, more powerful treatments can be used to slow the proliferation of skin cells, including phototherapy or oral medications. However, the skin can become resistant to treatment over time.

Creams and ointments

In all cases, the moisturizing or emollient creams can be useful in reducing itching and hydrate skin dried out by disease and frequent use of medicated creams. Choose a moisturizer for sensitive skin.

If the symptoms are mild or moderate, the dermatologist usually prescribes topical ointments intended to calm inflammation.

These are usually corticosteroid creams or creams retinoids (tazarotene, Tazorac® in Canada, Zorac® in France), to be applied alone or in combination. Calcipotriol cream (Dovonex® in Canada, Daivonex® in France, most often associated with a topical corticosteroid, in Daivobet® in France), a derivative of vitamin D, is also used to decrease the proliferation of cells in the epidermis. Corticosteroid creams should not be used over a prolonged period due to the risk ofSide effects (loss of pigmentation, thinning of the skin, etc.) and the gradual loss of effectiveness of the treatment. There are corticosteroid lotions and even shampoos for scalp lesions.

Phototherapy and PUVA-therapy

Light therapy involves exposing the skin to ultraviolet rays (UVB or UVA). They are used if the psoriasis covers a large part of the body or if the flare-ups are frequent. Ultraviolet rays slow cell proliferation and relieve inflammation.

These rays can come from various sources:

• Short, daily exhibitions at sun. Avoid prolonged exposure, which can make symptoms worse. Check with your doctor;
• A device for irradiating broad-spectrum or narrow-spectrum UVB rays;
• From an excimer laser device. UVB rays are then more powerful, but this therapy is still experimental²⁴.

Phototherapy is generally used in combination with an oral or topical medication that sensitizes the skin to the action of ultraviolet rays: this is called photochimiothérapie. For example, the PUVA therapy combines exposure to UVA rays with psoralen, a substance that makes the skin more sensitive to light. Psoralen is administered orally or by immersion in a “bath” before exposure to UVA. The short-term risks of PUVA therapy are negligible. In the long term, it would slightly increase the risk of skin cancer. To treat moderate to severe psoriasis, you need to do several sessions per week, for about 6 consecutive weeks.

Oral medication

For larger and more severe forms of psoriasis, drugs given by mouth or by injection are prescribed:

• The retinoids (acitretin or Soriatane®), often in combination with calipotriol or topical corticosteroids. The main side effects are dryness of the skin and mucous membranes. These drugs are also dangerous for the fetus during pregnancy and should only be taken with effective contraception.
• Le methotrexate or cyclosporine which decrease the activity of immune system (immunosuppressant) and are very effective, but which are reserved for short treatment phases due to the strong side effects (damage to the liver and kidneys, increased risk of infection).

If other treatments fail, so-called “biological” drugs (adalimumab, etanercept, infliximab) can be used.