Although there is no cure for psoriasis, topical medications are an invaluable tool for many people in managing the disease. Topicals—which are applied directly to the skin—can reduce itching and inflammation, improve the skin’s appearance, and normalize abnormal cell production, which is thought to be one of the causes of psoriasis.

If your condition is isolated to a few areas, topicals are the first line of defense, says Steven Feldman, MD, PhD, professor of dermatology at the Wake Forest University School of Medicine in Winston-Salem, N.C. “I divide patients into two groups: Those with a few spots where I use topicals, and those with so many spots that you can’t possibly put topicals on all of them.” For those with psoriasis that covers many areas, oral medications and biologics might be a better fit.

Your dermatologist may also decide to use topicals in combination with other medications. Make sure to apply them only to the part of the body directed by your doctor to avoid unwanted side effects.

Your topical tool kit

• Moisturizing creams. A key to treating psoriasis is keeping your skin moisturized. Patients recommend ointments such as Vaseline and lotions to minimize itching and redness; finding the right product is a process of trial and error. Whatever you choose, slather the affected parts of your body immediately after a bath or shower.

• Coal tar. How this age-old remedy helps psoriasis sufferers remains something of a mystery. “We have no idea how it works,” says Robert E. Kalb, MD, clinical associate professor of dermatology at the University at Buffalo School of Medicine in Buffalo, N.Y. Doctors presume that it reduces the overproduction of skin cells. The upside to tar products is that they don’t cause side effects. The downside is that they’re smelly and messy, and can stain fabric.

• Topical steroids. “Steroids are the mainstay of topical treatments,” says Dr. Kalb. Also known as topical corticosteroids, topical steroids are one of the most popular topical solutions and come in a wide range of potencies, from mild formulas available over the counter to heavy-duty prescriptions. Steroids decrease inflammation, relieve itching, and slow the development of new psoriasis patches. Although effective, aggressive topical steroids can cause skin thinning (which can lead to stretch marks), so many dermatologists recommend using them only for a short period of time. “The challenge is to maintain the benefits without using them too much,” says Dr. Kalb.

• Vitamin D analogues. Synthetic versions of vitamin D, these medications control the overproduction of skin cells, decreasing scaling and itching. They are not as fast acting as topical steroid products, but the upside is that they don’t have the skin-thinning side effects of steroids. Many doctors use them as a complement to steroids; once the psoriasis is under control with steroids, Dr. Kalb often switches his patients to a popular vitamin D derivative called Dovonex (also known by its generic name calcipotriene), or uses it in conjunction with lower doses of steroids. Another product called Taclonex combines calcipotriene with a steroid. “Of the patients that I treat who are candidates for topicals, 90% are treated with topical steroids or vitamin D derivatives,” says Neil Korman, MD, PhD, clinical director of the Murdough Family Center for Psoriasis in Cleveland.

• Vitamin A derivatives. Vitamin A derivatives such as Tazorac (also known as tazarotene) slow down the growth of skin cells and reduce inflammation. They are commonly used on areas such as the face, scalp, and nails, although they sometimes can cause skin irritation.

• Salicylic acid. This treatment, often used in conjunction with other topical remedies, reduces inflammation and helps remove scales that appear on psoriasis patches. Salicylic acid is available both over the counter and by prescription in lotions, soaps, shampoos, and other forms.

Finding one that works: It’s personal
Choosing the right treatment is a process of trial and error. You and your doctor should consider factors such as side effects, lifestyle choices, and cosmetic preferences to help you decide where to start. Once you begin experimenting, you will find out which approaches work best for you.

Researchers are not sure why success is so variable, but they speculate that some people respond better to certain treatments because of the genetic side to psoriasis. If this is true, says Dr. Kalb, understanding how different people react could greatly advance treatment options someday. “In the future, we might be able to do a blood or skin test to predict what will help them,” he says.

Until then, patients should work closely with their doctors to monitor and switch treatments when necessary. “If you use a topical medication for three to four weeks you should definitely see an improvement,” says Dr. Kalb. If not, your dermatologist will probably try something else.

Although topicals can be very effective, doctors say there is a high rate of noncompliance when it comes to applying them. “It’s a chronic disease, and sometimes people just use them for awhile, get tired of them, and then stop using them,” says Dr. Korman. For the best results, follow the directions from your doctor on how often to apply and, even though it can be bothersome, stick with it.

Psoriasis is a skin condition that can take many forms. Most people live with just one of the types below, although there are rare cases in which a patient may experience more than one type.

Plaque psoriasis
The most common type of psoriasis is plaque psoriasis. Nearly 90% of the people who live with psoriasis have this kind. Plaque psoriasis shows up as dry, red, raised lesions covered in silvery white scales that may shed. It usually appears on the elbows, knees, scalp, or lower back, although it can crop up anywhere, including the genitals and inside the mouth.

Guttate psoriasis
Up to 10% of people with psoriasis have guttate, the second most common type of the disease, which usually affects people under 30. In this form, the plaques are smaller and resemble water drops, and typically develop suddenly, often following a cold or upper respiratory tract infection. One of the major triggers of guttate psoriasis is strep throat. The plaques usually appear on the trunk, arms, legs, and scalp, and may be covered in a finer scale than those in plaque psoriasis.

Inverse psoriasis (also called seborrheic psoriasis)
Inverse psoriasis develops in skin folds such as the armpits, groin, under the breasts, around the genitals and buttocks, and sometimes behind the ears. It is exacerbated by friction and sweating. Most common in people who are overweight, it often starts out very red without much scale, and may appear shiny.

Pustular psoriasis
White blisters surrounded by red skin are the hallmarks of pustular psoriasis. The skin generally turns red first and then quickly develops noncontagious pustules filled with white blood cells. It usually covers a large swatch of skin and is sometimes accompanied by fever, chills, and severe itching. The blisters may clear quickly but reappear often.

This type of psoriasis has several triggers, including pregnancy and medications such as systemic steroids. Flares may also occur after stopping the use of certain medications, such as strong topical steroid creams.

Erythrodermic psoriasis
The least common form of psoriasis results in inflammation, itching, and a painful red rash that may peel and often covers the entire body. Sometimes accompanied by chills and unregulated body temperature, it can result from severe sunburn, withdrawal from systemic treatment, or another form of psoriasis that is not well controlled. People with erythrodermic psoriasis should seek immediate medical attention because it can lead to dangerous protein and fluid loss, swelling, infection, or pneumonia, and can require hospitalization.

Psoriatic arthritis
Up to 30% of people with psoriasis also have psoriatic arthritis, which usually develops five to 10 years after the original psoriasis diagnosis (although it can show up before a skin diagnosis). The primary symptoms are pain and stiffness in a joint or joints. Morning stiffness, which can take 45 minutes to loosen up, and tendinitis are two other signs.

If a person with psoriasis develops joint symptoms that last more than a few weeks, they should be evaluated to see if they have developed psoriatic arthritis. People with mild psoriasis might be just as likely to develop arthritis as someone with a severe form of the disease. Although psoriatic arthritis is not as debilitating as other forms of arthritis, it should be controlled to minimize pain and maximize joint function.