Sometimes we meet people whose elbows are reddish and covered with thick silver-white scales. That is only one of the symptoms of a disease called psoriasis. About .2% of the population suffers from this disease, but fortunately most of the cases are mild. Statistically there is no difference between men and women in the incidence of psoriasis. Most of the time the disease appears between the ages of ten and thirty, but its first manifestations can appear at any age. Psoriasis is not a communicable disease, and it usually does not cause itching or any other physical sensation.
SYMPTOMS OF PSORIASIS
As previously stated, psoriasis is characterized by red patches covered with white scales. It is most usually found on the elbows, the knees and the scalp. In more severe cases other areas of the body are affected, and in rare cases the entire body surface is involved. There are special forms of the disease in which only the palms of the hands and the soles of the feet are affected, or only the armpits and groin. In infants psoriasis first appears as severe diaper rash which does not respond to treatment. Although psoriasis is almost exclusively a skin disease, in about 5% of the cases there is involvement of the joints causing swelling and pain, sometimes to the point of disability. The nails are affected, losing their smoothness and thickening at the edges. The first sign of nail involvement is the appearance of small depressions in the nails or of small spots which have the appearance of drops of oil under the nails.
Characteristic Psoriasis Patches (Left - body, right- scalp).
THE CAUSES OF PSORIASIS The cause of psoriasis is unknown, but since 30% of psoriasis patients report that a family member also suffers from the disease, it is assumed that heredity plays a part. Evidence shows that psoriasis is linked to two processes. One is the process of inflammation, which causes dilation of the blood vessels and the redness typical of psoriasis, and the other is the increased production of new skin cells in the epidermis. As opposed to normal skin, in which the epidermis is renewed once a month, in psoriasis the cells multiply at an increased rate and the entire skin layer is replaced within a few days. The new cells are abnormal and accumulate on the skin in the form of thick, sticky scales. A person with a tendency to the disease can develop it at the site of a blow or scratch, in scar tissue, after a severe case of sunburn or as a result of prolonged nervous tension. In addition, psoriasis can appear after an infection of the throat (particularly in children) or as result of taking certain drugs. There are people who develop psoriasis after taking lithium, after taking beta-blocking drugs to reduce hypertension (Deralin, for example), and after taking anti-malarial drugs.
TREATING MILD TO MODERATE CASES OF PSORIASIS
Despite the fact that psoriasis cannot be cured, there are various treatments which will slow the rate at which the cells multiply and ease the inflammation. Suitable creams and ointments can greatly reduce the patches in most of the mild to moderate cases. The use of preparations containing salicylic acid will cause the thick scale to peel; preparations containing cortisone will depress the inflammation; preparations containing coal tar derivatives (Alphosyl, for example) and anthralin (Dithocream, Psoralon) reduce the rate at which the skin cells divide. In most cases, the combination of drugs appropriate for the individual patient causes a marked reduction in the symptoms and the skin appears almost normal. During the last few years it has been shown that prolonged use of preparations containing high concentrations of steroids cause irreversible damage to the skin. It has also been shown that the skin becomes accustomed to steroids to the point where the concentration must be increased every few weeks to achieve the same results. In addition, psoriasis patients noted that after the completion of steroid treatment there is often a worsening of the condition; this is known as the rebound phenomenon.
TREATING WIDESPREAD PSORIASIS
When psoriasis is spread over a large area of the body, the treatment is usually a combination of preparations containing coal tar derivatives and exposure to UVB ultra-violet rays. This treatment is called phototherapy and involves the use of a specially built apparatus. The treatment is given during a hospital stay averaging four weeks, or at phototherapy units which the patient visits several times a week. Phototherapy usually achieves remission after about thirty treatments. Another possible treatment for moderate to severe cases of psoriasis is exposure to the sun at the Dead Sea in Israel. As opposed to treatments at phototherapy units in which the patient is exposed to UVB for a few minutes at a time, the treatment at the Dead Sea requires the patient to be exposed to the sun for a few hours daily, and that demands a great deal of time. Another disadvantage of treatment at the Dead Sea is that it depends on the weather; the treatment is not effective during the winter. In the past fifteen years a new treatment, called PUVA, has been developed. It is based on a drug called Psoralen, which comes in pill form, and on exposure to UVA ultra-violet rays an hour and a half after the pills have been taken. The pills cause increased sensitivity of the skin and eyes to sunlight, and patients taking the drug must wear special sunglasses for at least 24 hours after the drug has been ingested. Treatments at the Dead Sea and at phototherapy units involve similar dangers to excessive exposure to the sun, including accelerated aging of the skin and the increased risk of skin growths.
INNOVATIONS IN PSORIASIS TREATMENTS
A new type of preparation, based on Vitamin D, may improve the treatment of mild to moderate cases. This ointment, called calcifortriol (brand name: Daivonex), is more convenient to use than those containing coal tar derivatives and safer than those containing cortisone. According to recent studies in Great Britain, hundreds of patients reported an improvement after using this product, without experiencing any significant side effects. Since its use is limited to 100 grams a week, it is unsuitable for treating cases of widespread psoriasis.
One of the greatest achievements in dermatology in the last few years was the development of a group of medications called the retinoids. These drugs, whose chemical composition is close to that of Vitamin A, brought about a breakthrough in the treatment of certain skin diseases, psoriasis among them.
One of these drugs, called Tigason, is suitable for the treatment of the severe cases of psoriasis which do not respond to ointments or phototherapy. Since this drug is teratogenic (may cause abnormalities in fetuses), it may not be taken within two years before a planned pregnancy, and any women of child-bearing age who does take it is required to use some sort of contraceptive device. An additional disadvantage of Tigason is that it produces a sticky sensation on the skin, slight peeling around the lips and fingernails and in rare instances an increase in blood lipids or an impairment of liver function. Despite these side effects, it is a particularly effective drug and greatly improves the quality of the patients’ lives.
Within the last few years out-patient clinics have been opened for psoriasis treatment. These clinics give the patients topical treatments during 3-4 hours, after which the patient is exposed to 10-20 minutes of ultraviolet radiation. The advantage of this method is that the patient can continue his or her regular routine without long hospital stays or trips to the Dead Sea. An additional advantage is that the patient comes home without any visible signs of having undergone treatment and does not have to use any unpleasant-smelling creams or ointments at home.
CAN PSORIASIS BE COMPLETELY CURED?
Unfortunately, psoriasis cannot be completely cured. No drug has yet been developed which can prevent psoriasis attacks once and for all. Proper treatment, however, can cause a remission for long periods of months or even years. This is possible if the treatment is geared to the severity of the disease and if treatment is continued even when there are very few symptoms present. Regular treatment of the disease even when it is in remission can prevent its worsening at a later stage.
Dr. Yoram Harth - more Info.