One size does not fit all when it comes to psoriasis treatments. How you ease symptoms of this chronic disease depends in large part on where psoriasis appears on your body. “We think of the skin as one organ, but it’s different in different places,” says Steven Feldman, MD, PhD, professor of dermatology at the Wake Forest University School of Medicine in Winston-Salem, N.C.

“The skin of the eyelid is completely different than the skin on the palm or the sole of the foot,” Dr. Feldman says. Because the skin in these areas will absorb medications differently, you need a tailored approach.

“When dealing with the sensitive skin of the face, you don’t need high potency. But when dealing with the palms or sole of the foot, you have to use the stronger stuff to get the adequate anti-inflammatory effects,” Dr. Feldman says. If your psoriasis is all over your body, systemic oral medications or biologics might be your best bet.

Here’s a rundown of common areas affected by psoriasis—and what you should know about treating them.

Scalp
Treat the scalp topically with medicated liquids, mousse, shampoo, sprays, gels, tar products, and soaps made especially for this difficult area. “Scalp psoriasis can be among the most recalcitrant,” says Neil Korman, MD, PhD, clinical director of the Murdough Family Center for Psoriasis in Cleveland. “Systemic therapy—pills or shots—may be necessary if a patient does not improve with an aggressive topical regimen.” Not only is psoriasis on the scalp stubborn, but treating it “can be incredibly time consuming and difficult to do,” Dr. Feldman says. It’s time consuming to get medication directly onto the scalp while avoiding the hair; tar products, while effective, can be smelly and stain light hair; and some scalp treatments must be left on overnight, which can be a messy proposition.

To make scalp treatments easier and more effective, the National Psoriasis Foundation recommends first removing any scales on the scalp so the medication can seep in more easily. Loosen them by soaking the scalp in warm water. The foundation also recommends rubbing some heated olive oil onto the scalp, wrapping your head in a towel and leaving it on for several hours, or using a hair dryer. Remove the scales carefully with a fine-tooth comb or brush before applying the treatment. If you need to leave the medicine on overnight, invest in a good, comfortable shower cap for less mess.

It’s common to use these treatments for about two months; once the psoriasis has cleared you can maintain this by using a medicated shampoo several times a week. Steroid creams and injections are also used for the scalp, although ideally in moderation. Other topical medications derived from vitamin D and A are also sometimes used.

Face
According to the National Psoriasis Foundation, the most common areas for facial psoriasis to appear are the forehead, upper lip, around the eyebrows, the upper forehead, and the hairline. Dermatologists try to avoid aggressive topical steroids in these highly delicate areas because they absorb medication readily and are prone to side effects such as skin thinning. Medications can also irritate the eyes.

Dermatologists usually start with mild topical steroids or topical immunomodulators, Dr. Korman says. If the patient doesn’t respond to these treatments, phototherapy or other systemic treatments might be appropriate. “If psoriasis on the face is causing major social-interaction problems, we need to be more aggressive,” Dr. Korman says.

Elbows and knees
These thick-skinned spots are ideal for topical steroids, salicylic acid, and coal tar. “In stubborn places such as the elbows and knees, I tend to use stronger topical steroid products or combinations of topical steroids and vitamin D analogues. I often tell patients to use topical medicine every day for a couple of weeks, and then taper off to once or twice a week,” says Robert E. Kalb, MD, clinical associate professor of dermatology at the University at Buffalo School of Medicine in Buffalo, N.Y.

Hands and feet
The first step in treating psoriasis on the hands and feet is to try moisturizers and mild soaps. If this doesn’t work, then a vitamin D derivative such as Dovonex and/or topical steroids should be next. If the psoriasis is severe, oral medications or a biologic might be the best course of action.

Genitals and skin folds
Psoriasis appearing in less visible parts of the body, such as the perineum, armpits, under the breasts, and around the genitals and buttocks, is known as inverse psoriasis. These sensitive areas can be breeding grounds for yeast or fungal infections, so your doctor might recommend adding an antifungal and yeast cream to your regular treatment to avoid such infections. Although topical steroids can be effective in these areas, Dr. Kalb tries to avoid using them here, opting instead for vitamin D analogues or topical calcineurin inhibitors. If the psoriasis is severe, he might prescribe topical steroids for a short period of time before switching over.

Psoriasis treatment usually proceeds by trial and error. Experts recommend using mild creams and phototherapy on affected areas at first. If your psoriasis is resistant or severe, your doctor might switch to systemic solutions, which include oral medications and biologics, either alone or in conjunction with some of the above treatments. The good news is that with so many options available, you and your doctor can take the time to find one that works best for you.

Oral medications have been used for decades to treat psoriasis. In recent years patients with moderate to severe psoriasis have increasingly switched to newer biologic medications, which are injected, but oral medications (also known as “systemics”) are still an important and commonly used treatment for psoriasis.

One of the main advantages of oral medications is how long the drugs have been around. “Most doctors are going to start you off with the medication that has the fewest side effects and the least chance of causing harm,” says Kathy Kavlick, RN, community outreach nurse for the Murdough Family Center for Psoriasis in Cleveland. In comparison to some of the newer psoriasis drugs on the market, Kavlick says, “these systemics have been around a lot longer, so we know a lot more about their long-term effects and what to watch for.”

If your psoriasis causes significant discomfort or pain or covers a sizable part of your body, your dermatologist is likely to discuss the possibility of using a systemic. Some insurance companies also require psoriasis patients to try an oral medication before starting a biologic, since biologics are far more expensive. The primary oral medications prescribed for psoriasis are methotrexate, cyclosporine, and acitretin.

Here’s what you should know about the different systemic medications:

Methotrexate
What it is: Methotrexate belongs to a class of drugs known as antimetabolites, and it works by interfering with the overproduction of skin cells that causes psoriatic plaques to develop. Methotrexate is usually taken once a week in a single dose of up to 30 mg, although it is sometimes broken up into three smaller doses spread out over a 24-hour period.

Efficacy: Studies have shown that methotrexate is effective in 70% to 80% of psoriasis patients. In a 2003 study of oral medications published in the New England Journal of Medicine, 60% of the patients who received methotrexate experienced partial remission; of those patients, 65% saw near-complete remission. Patients usually start to see results after two to three months.

Side effects: The most common side effect is nausea, which is usually alleviated by supplementing the drug with folic acid. Other side effects are more serious. Liver damage is a primary concern with methotrexate, especially for people who drink alcohol or who are diabetic or obese. (The risk of liver damage is high enough that, after taking the drug for a year or more, patients often require a liver biopsy to test for toxins in the organ.) Methotrexate can also cause birth defects and cannot be used during pregnancy.

Cyclosporine
What it is: Cyclosporine is an immunosuppressant drug that fights psoriasis by suppressing the faulty immune cells that signal skin cells to grow too quickly. It is usually taken once a day as a capsule or in liquid form.

Efficacy: In more than a dozen studies, cyclosporine has been shown to produce significant improvement in psoriasis in up to 90% of the patients who take it. One of its main benefits is that it works quickly, usually in as little as two weeks.

In the New England Journal of Medicine study mentioned above, cyclosporine slightly outperformed methotrexate. More than 70% of the patients who received cyclosporine experienced a partial remission, although less than half of them experienced near-complete remission. In a more recent study comparing three-month treatments of cyclosporine and methotrexate, patients saw their psoriasis symptoms decrease by 72% and 58%, respectively.

Side effects: Cyclosporine reduces the flow of blood through the kidneys, which impairs their function and can cause serious damage over time. Cyclosporine can also cause high blood pressure, although limiting the course of treatment to a few months appears to mitigate this side effect. Other relatively minor side effects include nausea, joint pain, headache, and fatigue. (Cyclosporine has also been shown to raise the risk of non-melanoma skin cancer six-fold, but only in patients who have previously undergone a type of phototherapy known as PUVA.)

Acitretin
What it is: Acitretin is a retinoid, a type of synthetic vitamin A. Usually known by its brand name, Soriatane, acitretin is taken as a once-a-day pill and is the only oral systemic not available as a generic. It is often combined with phototherapy.

Efficacy: What little research exists on the use of Soriatane alone has shown that it can produce mild to moderate clearance. Soriatane seems to be most effective and useful as an addition to phototherapy, however. A pair of studies that compared the combination of UVB phototherapy and Soriatane with the phototherapy alone found that adding Soriatane more than doubled the number of patients who experienced improvement or clearing of their psoriasis.

Side effects: Most of the side effects associated with Soriatane are minor. They include lip inflammation, dry mouth, skin thinning and fragility, joint and muscle pain, and hair loss (alopecia). Potentially more serious side effects include liver damage, skeletal abnormalities, and an elevation of cholesterol and triglycerides. Soriatane is also known to cause birth defects, so it is not an option for women who may become pregnant.

How are they used?
Each systemic medication has its own advantages and potential complications. Although patients sometimes stay on one medication for months (or even years), dermatologists have found that they may be able to maximize the advantages and minimize the complications of these drugs by prescribing them in sequence.

Methotrexate and cyclosporine clear psoriasis more quickly than Soriatane, for instance, but are less appropriate for long-term “maintenance” therapy due to the potential for liver and kidney damage. Cyclosporine, for instance, cannot be taken continuously for more than a year. Some dermatologists will therefore prescribe an initial dose of methotrexate or cyclosporine, add Soriatane after a month or two, and then gradually taper off the more powerful systemic.

In other cases, dermatologists will simply rotate through the various systemic medications to lessen the risk of side effects. Systemic drugs are also frequently prescribed in combination. This appears to enhance their efficacy, and it also allows each drug to be given in lower doses, which minimizes the potential for any one long-term side effect.