ALLERGIC CONTACT DERMATITIS

Contact dermatitis is a condition in which people develop an allergy to a product or substance that comes in contact with the skin.  The condition is usually manifested as a rash on the skin and can occur on the face and eyelids, a condition called eyelid and facial contact dermatitis.

The usual suspect: Nickle

A common irritant responsible for allergies includes nickle. Nearly 6% of Americans are allergic to nickel, making the silver-white metal the second most common cause of allergic skin rashes, behind only poison ivy. The incidence of nickel sensitivity among women is higher than the average, probably around 10 percent. Other common cosmetic ingredients responsible for allergic contact dermatitis:

• Preservatives (parabens, phenyl mercuric acetate, imidazolindnyl urea, quaternium-15, potassium sorbate)
• Resins (colophony)
• Pearlescent Additives (bismuth oxychloride)
• Antioxidants (butylated hydroxyanisole, butylated hydroxytoluene, di-tert-butyl-hydroquinone)
• Emollients (lanolin, propylene glycol)
• Fragrences
• Pigmented Contaminants (nickel)

An unusual suspect: Latex

Natural rubber latex is responsible for a recent and widespread outbreak of allergic skin reactions, ranging from mild irritation to anaphylactic shock. Latex reactions were rarely reported prior to 1970, but increasing numbers of reports since the late 1980's have led scientists to believe that increased exposure to latex products in recent years has caused more people to become sensitized. About a third of those who develop hives from contact with latex also develop such symptoms as asthma and even anaphylactic shock. This should lead people who suspect they are allergic to latex to have a professional diagnosis.

Location, location, location: Dermatitis on eyelids and faces

The skin of the face and especially the eyelid is the thinnest skin on the body and is the most susceptible to irritant and allergic contact dermatitis. Frequently, the cause is a reaction to cosmetics, either applied to the face, eyes, or in the case of nail polish, to the nails. It may be necessary to do standard patch resting and to do individual testing on the specific products that one uses.

Finding the culprit

Finding the source of the allergy requires some good detective work. Have you recently changed fragrance? Have you use a new soap, shampoo, or laundry detergent? Has the same brand you've always used been reformulated? If you have recurrent problems, try keeping a diary of the products you use, and note when the symptoms start to appear and/or stop.

Should you develop a contact dermatitis, see your dermatologist for relief. He/she can perform a patch test to determine the irritating substance. If you suspect a nickel allergy, it is a good idea to have the dermatologist test for nickel sensitivity when considering having ears pierced. In any case, the piercing should be done with a stainless-steel needle. As a further precaution, stainless-steel or high-quality 18 karat gold studs should be worn as the first pair of earrings. Nickel sensitivity often does not result in a rash for weeks or months after contact with the metal. To further confuse the issue, a rash may not necessarily occur on the part of the body that makes contact with the metal.

Treatment

• Discontinue all facial cosmetics, previously prescribed topical medications, fragrances, and toiletries for two weeks. You may wash with plain water, Cetaphil, or Spectroderm cleansers.

• Eliminate all sources of eyelid skin friction, such as rubbing the eyes and eyeglasses.

• Once the dermatitis is improved, add one facial cosmetic of low allergenic potential per week in the following order: lipstick, face powder, powder blush, foundation.

• Eyelid cosmetics should be individually tested by applying them to a one inch square area behind the right ear nightly for five nights. If no irritation develops, then the cosmetic preparation should be applied to a one inch square area lateral to the eye for five nights. They should be tested in the following order: mascara, eyeliner, eyebrow pencil, and eye shadow.

• Over the counter treatment products and other miscellaneous skin care products designed for leave-on use should be individually tested by applying them nightly, for at least five nights to a one inch square area lateral to the eye.

• Ask your dermatologist about new topical non-steriod medications, such as Elidel, which could improve your condition.

Tips for selecting cosmetics for sufferers of eyelid dermatitis:

• When possible, powder cosmetics should be selected over cream or lotion formulations.
• All cosmetics should be easily removed by water. No waterproof cosmetics should be selected.
• Old cosmetics should be discarded and fresh product purchased.
• Eyeliner and mascara should be selected in the color black.
• Pencil forms of eyeliner and eyebrow cosmetics should be used.
• Eye shadows should be selected from the light earth tones; colors such as cream and tan. Deep colors, such as blues, purples, and greens should be avoided.
• Select cosmetics without chemical sunscreen agents (PABA, methoxycinnamates, etc.) Usually titanium dioxide can be tolerated.
• Purchase cosmetic products with no more than ten ingredients, if possible.
• Facial foundations should be of the cream/powder variety or, if of the liquid type, based on silicone derivatives (cyclomethicone, dimethicone).
• Avoid nail polishes.

Dermatitis goes outside: Poison Ivy, Sumac, and Oak Rashes

Poison ivy rash is really an allergic contact dermatitis caused by a substance called urushiol, found in the sap of poison ivy, poison oak, and poison sumac. Urushiol is a colorless or slightly yellow oil that oozes from any cut, or crushes part of the plant, including the stem and the leaves.

You may develop a rash without ever coming into contact with poison ivy, because the urushiol is so easily spread. Sticky and virtually invisible, it can be carried on the fur of animals, on garden tools, or sports equipment, or on any objects that have come into contact with a crushed or broken plant. After exposure to air, urushiol turns brownish-black, making it easier to spot. It can be neutralized to an inactive state by water.

Once it touches the skin, the urushiol begins to penetrate in a matter of minutes. In those who are sensitive, a reaction will appear in the form of a line or a streak of rash (sometimes resembling insect bites) within 12-48 hours. Redness and swelling will be followed by blisters and severe itching. In a few days, the blisters become crusted and begin to scale. The rash will usually take about ten days to heal, sometimes leaving small spots, especially noticeable in dark skin. The rash can affect almost any part of the body, especially areas where the skin is thin; the soles of the feet and palms of the hands are thicker and less susceptible.

Recognizing poison ivy

Identifying the plant is the first step toward avoiding poison ivy. The popular saying “leaves of the three, let them be” is a good rule of thumb, but it’s only partially correct. Poison oak or poison ivy will take on a different appearance depending on the environment. The leaves may vary from groups of three, to groups of five, seven, or even nine.

Poison oak is found in the West and Southwest, poison ivy usually grows east of the Rockies, and poison sumac east of the Mississippi River. The plants grow near streams and lakes and wherever there are warm humid summers.

Poison ivy grows as a low shrub, vine, or climbing vine. It has yellow-green flowers and white berries. Poison oak is a low shrub or small tree with clusters of yellow berries and the oak-like leaves. Poison sumac grows to a tall, rangy shrub producing 7-13 smooth-edged leaves, and cream colored berries. These weeds are most dangerous in the spring and summer. That’s when there is plenty of sap and urushiol content is high, and the plants are easily bruised. Although poison ivy is usually a summer complaint, cases are sometimes reported in winter, when the sticks may be used for firewood, and the vines for Christmas wreaths. The best way to avoid these toxic plants is to know what they look like in your area and where you work, and to learn to recognize them in all seasons

Treatment

If you think you’ve had a brush with poison ivy, poison oak or poison sumac, follow this simple procedure:

• Wash all exposed areas with cold running water as soon as you can reach a stream, lake or garden hose. If you can do this within five minutes, the water will neutralize or deactivate the urushiol in the plant’s sap and keep it from spreading to other parts of the body. Soap is not necessary and may even spread the oil.

• When you return home, wash all clothing outside, with a garden hose, before bringing it into the house where resin could be transferred to rugs or furniture. Handle the clothing as little as possible until it is soaked. Since urushiol can remain active for months, it’s important to wash all camping, sporting, fishing or hunting gear that may also be carrying resin.

• If you do develop a rash, avoid scratching the blisters. Although the fluid in the blisters will not spread the rash, fingernails may carry germs that could cause infection.

• Cool showers will help ease the itching and over-the-counter preparations, like calamine lotion, or Burrow’s solution, will relieve mild rashes. Soaking in a lukewarm bath with an oatmeal or baking soda solution is often recommended to dry oozing blisters and offer some comfort. Over-the-counter hydrocortisone creams will not help. Dermatologists say they aren’t strong enough to have any effect on poison ivy rashes.

• In severe cases, prescription corticosteroid drugs can halt the reaction if taken soon enough. If you know you’ve been exposed and have developed severe reactions in the past, be sure to consult your dermatologist. He or she may prescribe steroids, or other medications, which can prevent blisters from forming.

ATOPIC DERMATITIS

Atopic dermatitis is a disease that causes itchy, inflamed skin and typically affects the insides of the elbows, backs of the knees, and the face. Often, however, it covers most of the body. Atopic dermatitis falls into a category of diseases called atopic, a term originally used to describe the allergic conditions asthma and hay fever. Atopic dermatitis was included in the atopic category because it often affects people who either suffer from asthma and/or hay fever or have family members who do. Physicians often refer to these three conditions as the “atopic triad.”

Is eczema the same as atopic dermatitis ?

Although the term eczema is often used for atopic dermatitis, there are several other skin diseases that are eczemas as well. Eczema is a general term for all types of dermatitis. Dermatitis is a medical term meaning “inflammation of the skin.”

Atopic dermatitis tends to be the most severe and chronic (long lasting) kind of eczema. Often, people with atopic dermatitis have other skin conditions as well, especially dry skin, ichthyosis, occupational dermatitis, contact dermatitis, or hand eczema. This overlap of atopic dermatitis with other conditions makes atopic dermatitis even more difficult to control.

What substances trigger atopic dermatitis?

People with atopic diseases are unusually sensitive to certain agitating substances. Some of these substances are irritants and others are allergens. When people with atopic dermatitis are exposed to an irritant or allergen to which they are sensitive, cells that produce inflammation come into the skin. There, they release chemicals that cause itching and redness. Further damage is done when the person then scratches and rubs the affected area.

Some triggers are:

• Irritating substances (irritants and allergens)
• Dry skin
• Low humidity
• Skin infections
• Heat, high humidity, and sweating
• Emotional stress

Treatment

Sufferers of atopic dermatitis always have very dry, brittle skin. The external layer of skin called the stratum corneum acts as a barrier, protecting what lies underneath. When the stratum corneum cracks because of dryness, irritants can reach the sensitive layers below and cause a flare up of atopic dermatitis .

To prevent dry skin, the best and safest treatment is the use of moisturizers. Moisturizers provide a layer of oil on the surface of the skin, trapping water beneath and thus making the skin more flexible and less likely to crack.

Researchers have found that the most effective moisturizer is a petroleum based product such as Vasoline. Next best is a skin cream. Some heavy creams can be softened for application by warming in a microwave oven.

Generally, lotions (which have a high water content) actually dry the skin more than moisturizing it, and are therefore not recommended for sufferers of atopic dermatitis . People with atopic dermatitis need not avoid bathing or the use of soaps (which can dry the skin) as long as they:

1. Use warm (not hot) water
2. Avoid excessive use of soap, scrubbing, and toweling
3. Apply a moisturizer to the skin within three minutes after bathing

What if I get an infection?

People with atopic dermatitis are prone to skin infections, especially staph and herpes. In general, infections are hard to prevent. However, many-including staph and herpes-can and should be treated promptly to avoid aggravating the atopic dermatitis .

Signs to watch for include:

• Increased redness
• Pus-filled bumps (pustules)
• And cold sores or fever blisters

Sometimes viral “colds” or “flu” cause flare-ups of atopic dermatitis . With extra skin care for a few days while the virus runs its course, severe worsening can be avoided. If these signs appear, see a physician.

When atopic dermatitis flares up, what can be done?

As mentioned, the best line of defense against Atopic dermatitis is prevention. However, it is not likely that all flare-ups can be avoided. Once inflammation begins, prompt treatment as directed by a physician is needed. Bathing or wet compresses may ease the itch. Cortisone “steroid” creams, applied directly to the affected area, are helpful and a mainstay of therapy. Overuse of highly potent steroids can be damaging. Cortisone pills or shots are sometimes used, but they are not safe for long-term use. Many companies are testing new and safer drugs that control the itch and inflammation.

CHILDHOOD ATOPIC DERMATITIS

Atopic dermatitis, often called eczema, or atopic eczema, is very common skin disease. It affects around 10% of all infants and children. The exact cause is not known, but atopic dermatitis results from a combination of family heredity and a variety of conditions in everyday life that trigger the red, itchy rash.

How do we know if it is atopic dermatitis?

• Time of onset. This type of eczema usually begins during the first year of life and almost always within the first five years. It’s seldom present at birth, but it often comes on after six weeks. Other rashes also can start at that time, so it may be confusing at first but most rashes disappear within a few days to weeks. Atopic dermatitis tends to persist. It may wax and wane, but it keeps coming back.

• Itching. Atopic dermatitis also is a very itchy rash. Much of the skin damage comes from scratching and rubbing that the child cannot control.

• Location. The location of the rash also helps us recognize atopic dermatitis. In babies, the rash usually starts on the face or over elbows or knees, places that are easy to scratch and rub. It may spread to involve all areas of the body, although the moist diaper region is often protected. Later in childhood the rash is typically in the elbows and knee folds. Sometimes, it only affects the hand, and at least 70% of people with atopic dermatitis have had eczema at some time in their life. Rashes on the feet, scalp, or behind the ears are other clues that might point to atopic dermatitis.

• Appearance. The appearance of the rash is probably the least helpful clue because it may be very different from one person to another.

• Heredity. If other family members or relatives have atopic dermatitis, asthma, or hay fever, the diagnosis of atopic dermatitis is more likely.

What causes atopic dermatitis?

Atopic dermatitis is not contagious. People with atopic dermatitis cannot “give” it to someone else. Atopic dermatitis inflammation results from too many reactive inflammatory cells in the skin. Research is seeking the reason why these cells over-react. Patients with atopic dermatitis (or asthma or hay fever) are born with these over-reactive cells. When something triggers them, they don’t turn off as they should. We try to control atopic dermatitis by preventing the trigger factors that turn on the inflamed skin, or by “damping the flames” with anti-inflammatory therapies.

What triggers atopic dermatitis?

Trigger factors may be different for different people. Most children are worse when they have a cold or other infection. Most have worse problems in the winter; but others simply can’t stand the sweating during hot, humid summer weather. Let’s look at the trigger factors that seem to affect every child with atopic dermatitis.

• Dry skin
• Irritants
• Stress
• Heat and sweating
• Infections
• Allergens

How can you avoid triggers?

1. Keep the skin barrier intact. MOISTURIZE
2. Wear soft clothes that “breathe.” Avoid fabrics of wool, nylon, or stiff material.
3. If sweating causes itch, find ways to keep cooler. Such as:
4. Reduce exertion, especially during times of flare.
5. Layer clothing and adjust temperature settings.
6. Don’t overheat rooms, especially the bedroom.
7. Use light bedclothes.
8. When itching from sweating, dust, pollen, or other exposures, take a cooling shower or tub bath.
9. Learn to recognize signs of infection and treat early.

If you suspect food allergy, be systematic. Likely offenders are eggs, milk, peanuts, soy, wheat, and seafood, but any food can do it. Can you exclude the most likely offender for a week? Substitute hydrolysate for cow formula. Keep a food diary. When the skin clears up, try the food. Watch for signs if itching or redness over the next two hours. Do not try a suspect food if it causes hives or face swelling. Don’t exclude multiple food groups at the same time. It is rare to have more than one or two food allergies, and your child can get malnourished with prolonged avoidance of many foods.

With allergy-prone kids, furry animals are a risk. If you must have pets, keep    them outside or at least off beds, rugs, and furniture where the child plays. Dust mites collect in bedroom carpets and bedding. Simple control measures include covering pillows and mattresses, removing bedroom carpets and frequent washing of bedclothes in hot water.

Think about stress-causing events and ways to cope with them. Review problems with your doctor. Try to make atopic dermatitis treatments part of a daily, family routine. Encourage children with atopic dermatitis to do what they can on their own.

Treatment

• Moisturizers. Ointments such as petroleum jelly (such a Vasoline) are best unless they are too thick and cause discomfort. Creams may be fine for moderately dry skin or in hot, humid weather. Apply them to wet skin, immediately after bathing. Lotions and oils are not rich enough and often have a net drying effect on atopic dermatitis on skin.

• Corticosteroids. Often called topical (applied to the skin) steroids, these are cortisone-like-medications used in creams or ointments which your doctor may prescribe (Hydrocortisone, Desonide, Triamcinolone). They are not the same as the dangerous “steroids” some athletes misuse. Cortiscosteroid medicines are very helpful. Often they are the only treatment that can calm the inflamed skin.

Use of steroid ointments and creams requires good judgement and careful supervision. They come in strengths from mild to super-potent. Hydrocortisone is quite safe. The more potent ones can cause thinned skin, stretch marks, and other problems if used too many days in the same areas of the body. Parents should monitor the child’s use. Ask the doctor about potency and side effects of prescribed corticosteroid medicines.

• Antibiotics. Oral or topical antibiotics reduce the surface bacterial infections that may accompany flares of atopic dermatitis.

• Antihistamines. Often prescribed to reduce itching, these medicines may cause drowsiness but seem to help some children.

• Tar preparations. Tar creams or bath emulsions can be helpful for mild inflammation.

When will my child outgrow atopic dermatitis?

NUMMULAR DERMATITIS          

Nummular dermatitis gets its name from the Latin word nummulus, which means coin-like or coin-shaped. It is a very common skin rash in which patients report the onset of round, coin shaped, itchy lesions on a background of dry skin. They are frequently located on the lower leg, but may also be found on the arms and the trunk, especially the back. It most commonly affects men and women in the 50s and 60s, but also may affect younger people, even children in especially dry climates and in the winter.

The cause of nummular dermatitis is not known. It is related to dry skin and is aggravated by wool, soaps, frequent bathing, and many over the counter topical medications. Up to 90% of patients have Staph aureus colonizing the lesions. This suggests that nummular dermatitis may be a hypersensitivity reaction to the bacteria. Alcohol abuse has been reported to be associated with nummular dermatitis, and it may be that alcohol suppresses the immune response making those patients more susceptible to bacterial infection.

Treatment

There is no cure for nummular dermatitis, but it can be controlled. Topical steroids are the mainstay of therapy. Frequently, a very potent steroid ointment is applied initially, and then a less potent one is used if maintenance therapy is needed. Often a course of oral antibiotics is given if there are signs of infection. Long term prevention involves hydrating the skin by using a nondrying cleanser such as Cetaphil, Spectroderm, or Oil ition, applying a moisturizing oil within three minutes after a bath or shower will hold the moisture in the skin.

PERI-ORAL DERMATITIS          

This is an acne like eruption which usually occurs in women aged 25 and over, many of whom never had problems with their complexions when they were younger. It may occur in children and in men but less frequently.

There are pimple like bumps on the chin and around the mouth or lower ose areas. Frequently there is some redness to the skin in these areas.

The cause of this condition in uncertain, but it may occur after stopping birth control pills or during or after pregnancy. Recently studies have implicated excess fluoride as a cause: either fluoride toothpaste, mouthwash, or in strong cortisone-containing creams or ointments applied to the area.

Treatment

Treatment of peri-oral dermatitis includes the use of an oral or topical antibiotic and an additional prescription medication for the skin. During the one to two months of therapy it is also recommended that one avoid any fluoride toothpaste, mouthwash, or creams. Toothpaste without fluoride is difficult to find. Sensadyne without fluoride is one acceptable toothpaste.

Most cases respond well to treatment, but it may be necessary to continue treatment and supervision for several months before gradually discontinuing the medications which helped clear the skin.

SEBORRHEIC DERMATITIS

Seborrheic dermatitis is a common, harmless, scaling rash that sometimes itches. Dandruff is seborrheic dermatitis of the scalp. Seborrheic dermatitis may also occur on the eyebrows, eyelid edges, ears, the skin near the nose and such skin-fold areas as the armpits and groin. Sometimes seborrheic dermatitis produces round, scaling patches on the midchest or scales on the back.

What causes seborrheic dermatitis?

Seborrheic dermatitis results from skin not growing properly. The cause is not known. Seborrheic dermatitis is not related to diet and is not contagious. Nervous stress and any physical illness tend to worsen seborrheic dermatitis, but do not cause it.

Seborrheic dermatitis may appear at any age, either gradually or suddenly. It tends to run in families. Seborrheic dermatitis may last for may years and may disappear by itself. Often, it gets better or worse without any apparent reason.

Treatment

There is no cure for seborrheic dermatitis. However, we can keep this nuisance under control. The treatment of seborrheic dermatitis depends on what part of the body is involved. Dandruff, seborrheic dermatitis, of the scalp can usually be controlled by washing your hair often with medicated shampoos. Sometimes it is necessary to use lotions or gels containing tar or cortisone. In areas of smooth skin such as the face and ears, cortisone containing creams, lotions, or ointments are effective. Cortisones applied to limited areas of the skin do not affect your general health.

Once seborrheic dermatitis is under control, gradually use your medicines less and less. It may even be possible to stop the medicines completely, but usually occasional treatment is needed. Seborrheic dermatitis has a way of returning. If it does, resume the original treatment. If your seborrheic dermatitis is not controlled by the treatment prescribed, please return for further evaluation.

PSORIASIS

Psoriasis is a chronic skin disorder that is not contagious. It is more likely to occur in individuals whose family members have it. In the United States two out of every one hundred people have psoriasis (three to four million persons). There will be approximately 150,000 new cases of psoriasis each year.

Psoriasis got its name from the Greek word meaning “itch.” It is caused by an overproduction of sin cells. This leads to thickening of the skin and scaling. The disease appears as red areas with silvery scales that occur most often on the scalp, elbows, knees, and lower back.

In some cases, psoriasis is so mild that people never know they have it. In rare cases, others have such severe psoriasis that it resists therapy. At its worst, the disease can cover the entire body with redness and scales. Fortunately, this is rare. There are helpful treatments available for even the most severely affected patients.

What causes psoriasis?

The cause of psoriasis is unknown. Scientists speculate that a biochemical malfunction triggers skin cells to over-produce. In a person with psoriasis a skin cell matures in three to four days instead of the normal 28-30 days. People often experience their first attack or flare up about 10-14 days after the skin is cut, scratched, rubbed or severely sunburned. Psoriasis can also be triggered by some infections, such as strep throat, and by certain drugs.

Special diets have not been successful in preventing recurrences or improving existing psoriasis. People who live in cold weather climates often have flare ups in the winter due to dry skin and a lack of available sunlight.

What are the types of psoriasis?

Psoriasis occurs in a variety of forms that differ in their severity, duration, location and the shape and pattern of scales. The most common form begins with little red bumps. Gradually they grow larger and silvery scales form. While the top scales flake off easily and often, those below the surface stick together so that when they are removed, bleeding occurs. The small red areas grow, sometimes becoming quite large. They may be shaped like a small doughnut with a clear center, a coin or a rough oyster shell.

Elbows, knees, the groin, arms, legs, scalp, and nails are the most commonly affected areas. The psoriasis will often appear on both sides of the body in the same areas.

Treatment

The exact treatment recommended by a dermatologist will be based on a person’s overall health, age, lifestyle and the severity of the psoriasis. Different types of treatments and several visits to the dermatologist may be needed before the psoriasis comes under control. The goal of treatment of psoriasis is to ease discomfort and slow down rapid skin cell division. Moisturizing creams and lotions can improve the patient’s appearance and can also control itching.

Some forms of treatment are discussed below:

• Light therapy. Sunlight and ultraviolet light, type B (UVB), help psoriasis by slowing down the rapid growth of skin cells. Long term use of either form of light can cause premature aging of the skin, eye damage and skin cancer. However, given under a doctor’s care, this treatment can be safe. People with psoriasis all over their bodies may prefer treatment in a medically approved center equipped with UVB light boxes for full body exposure. An average of 40 whole body treatments is usually needed before the lesions subside or disappear. People who live in areas with year-round warm climates may be able to sunbathe for a prescribed number of hours. However, dermatologists warn people with psoriasis to seek advice about their medical condition before treating themselves.

• PUVA. A treatment called PUVA is used for patients who have not responded to other methods or who have more than 30% of their bodies covered with psoriasis. It is effective in 85 to 90% of the patients. Patients are given a drug called psoralen before being exposed to a carefully measured amount of ultraviolet light, type A (UVA), in a light box. PUVA treatments must be carefully monitored by a doctor. About 25 treatments are given over a two or three month period before clearing occurs. Then, the patient usually requires “maintenance therapy” or around 30 treatments a year.

PUVA treatments over a long period of time increase a person’s risk of skin aging, freckling, and skin cancer. Those who probably should not have this treatment are patients under the age of 18, pregnant women, patients with previous exposure to arsenic or ionizing radiation, and patients with skin cancer or certain types of sever eye disease.

• Methotrexate. Methotrexate is an oral anti-cancer drug that can produce dramatic clearing of psoriasis. However, it is not used unless other treatments have failed because it can produce serious side effects, notably liver disease. Periodic tests for liver and kidney function, liver biopsies, and chest x-rays are required. For the first two months of therapy, a patient should have weekly blood tests and at less frequent intervals thereafter. Other side effects include an upset stomach and lightheadedness. Psoriasis can recur when treatment is stopped.

• Retinoids. Vitamin A derivatives, particularly etretinate, may be prescribed for severe cases of psoriasis. This oral medication may be used in combination with ultraviolet light or alone.

A synthetic retinoid, Tazarotene, improved symptoms in clinical tests in 70% of those who had psoriasis on as much as 20% of their bodies. It is speculated that these synthetic retinoids accomplish this improvement by normalizing the speed at which skin cells produce and shed, as well as by reducing inflammation. And, unlike most topical treatments, tazarotene requires only one application daily. Patients who have many scaly patches scattered over their bodies find the once-daily regimen to be very appealing.

These drugs are usually reserved for severe cases of psoriasis because of the side effects. These include dry skin and eyes, elevation of fat levels in the blood, and formation of bony spurs in the spine. Because severe birth defects result in pregnant women who take these medications, it should not be used by young women of child-bearing age. This medication requires close monitoring by a dermatologist.