Psoriasis treatments aim to:
• Interrupt the cycle that causes an increased production of skin cells, thereby reducing inflammation and plaque formation.
• Remove scale and smooth the skin, which is particularly true of topical treatments that you apply to your skin.
Psoriasis treatments can be divided into three main types: topical treatments, light therapy and oral medications.
Used alone, creams and ointments that you apply to your skin can effectively treat mild to moderate psoriasis. When the disease is more severe, creams are likely to be combined with oral medications or light therapy. Topical psoriasis treatments include:
• Topical corticosteroids. These powerful anti-inflammatory drugs are the most frequently prescribed medications for treating mild to moderate psoriasis. They slow cell turnover by suppressing the immune system, which reduces inflammation and relieves associated itching. Topical corticosteroids range in strength, from mild to very strong. Low-potency corticosteroid ointments are usually recommended for sensitive areas, such as your face or skin folds, and for treating widespread patches of damaged skin. Your doctor may prescribe stronger corticosteroid ointment for small areas of your skin, for persistent plaques on your hands or feet, or when other treatments have failed. Medicated foams and scalp solutions are available to treat psoriasis patches on the scalp. To minimize side effects and to increase effectiveness, topical corticosteroids are generally used on active outbreaks until they're under control.
• Vitamin D analogues. These synthetic forms of vitamin D slow down the growth of skin cells. Calcipotriene (Dovonex) is a prescription cream, ointment or solution containing a vitamin D analogue that may be used alone to treat mild to moderate psoriasis or in combination with other topical medications or phototherapy.
• Anthralin. This medication is believed to normalize DNA activity in skin cells. Anthralin (Dritho-Scalp) can also remove scale, making the skin smoother. However, anthralin stains virtually anything it touches, including skin, clothing, countertops and bedding. For that reason doctors often recommend short-contact treatment — allowing the cream to stay on your skin for a brief time before washing it off. Anthralin is sometimes used in combination with ultraviolet light.
• Topical retinoids. These are commonly used to treat acne and sun-damaged skin, but tazarotene (Tazorac, Avage) was developed specifically for the treatment of psoriasis. Like other vitamin A derivatives, it normalizes DNA activity in skin cells and may decrease inflammation. The most common side effect is skin irritation. It may also increase sensitivity to sunlight, so sunscreen should be applied while using the medication. Although the risk of birth defects is far lower for topical retinoids than for oral retinoids, your doctor needs to know if you're pregnant or intend to become pregnant if you're using tazarotene.
• Calcineurin inhibitors. Currently, calcineurin inhibitors (tacrolimus and pimecrolimus) are only approved for the treatment of atopic dermatitis, but studies have shown them to be effective at times in the treatment of psoriasis as well. Calcineurin inhibitors are thought to disrupt the activation of T cells, which in turn reduces inflammation and plaque buildup. The most common side effect is skin irritation. Calcineurin inhibitors are not recommended for long-term or continuous use because of a potential increased risk of skin cancer and lymphoma. Calcineurin inhibitors are only used with your doctor's input and approval. They may be especially helpful in areas of thin skin, such as around the eyes, where steroid creams or retinoids are too irritating or may cause harmful effects.
• Salicylic acid. Available over-the-counter (nonprescription) and by prescription, salicylic acid promotes sloughing of dead skin cells and reduces scaling. Sometimes it's combined with other medications, such as topical corticosteroids or coal tar, to increase its effectiveness. Salicylic acid is available in medicated shampoos and scalp solutions to treat scalp psoriasis.
• Coal tar. A thick, black byproduct of the manufacture of petroleum products and coal, coal tar is probably the oldest treatment for psoriasis. It reduces scaling, itching and inflammation. Exactly how it works isn't known. Coal tar has few known side effects, but it's messy, stains clothing and bedding, and has a strong odor. Coal tar is available in over-the-counter shampoos, creams and oils.
• Moisturizers. By themselves, moisturizing creams won't heal psoriasis, but they can reduce itching and scaling and can help combat the dryness that results from other therapies. Moisturizers in an ointment base are usually more effective than are lighter creams and lotions.
Light therapy (phototherapy)
As the name suggests, this psoriasis treatment uses natural or artificial ultraviolet light. The simplest and easiest form of phototherapy involves exposing your skin to controlled amounts of natural sunlight. Other forms of light therapy include the use of artificial ultraviolet A (UVA) or ultraviolet B (UVB) light either alone or in combination with medications.
• Sunlight. Ultraviolet (UV) light is a wavelength of light in a range too short for the human eye to see. When exposed to UV rays in sunlight or artificial light, the activated T cells in the skin die. This slows skin cell turnover and reduces scaling and inflammation. Brief, daily exposures to small amounts of sunlight may improve psoriasis, but intense sun exposure can worsen symptoms and cause skin damage. Before beginning a sunlight regimen, ask your doctor about the safest way to use natural sunlight for psoriasis treatment.
• UVB phototherapy. Controlled doses of UVB light from an artificial light source may improve mild to moderate psoriasis symptoms. UVB phototherapy, also called broadband UVB, can be used to treat single patches, widespread psoriasis and psoriasis that resists topical treatments. Short-term side effects may include redness, itching and dry skin. Using a moisturizer may help decrease these side effects.
• Narrowband UVB therapy. A newer type of psoriasis treatment, narrowband UVB therapy may be more effective than broadband UVB treatment. It's usually administered two or three times a week until the skin improves, then maintenance may require only weekly sessions. Narrowband UVB therapy may cause more severe and longer lasting burns, however.
• Photochemotherapy, or psoralen plus ultraviolet A (PUVA). Photochemotherapy involves taking a light-sensitizing medication (psoralen) before exposure to UVA light. UVA light penetrates deeper into the skin than does UVB light, and psoralen makes the skin more responsive to UVA exposure. This more aggressive treatment consistently improves skin and is often used for more severe cases of psoriasis. PUVA involves two or three treatments a week for a prescribed number of weeks. Short-term side effects include nausea, headache, burning and itching. Long-term side effects include dry and wrinkled skin, freckles and increased risk of skin cancer, including melanoma, the most serious form of skin cancer.
• Excimer laser. This form of light therapy, used for mild to moderate psoriasis, treats only the involved skin. A controlled beam of UVB light of a specific wavelength is directed to the psoriasis plaques to control scaling and inflammation. Healthy skin surrounding the patches isn't harmed. Excimer laser therapy requires fewer sessions than does traditional phototherapy because more powerful UVB light is used. Side effects can include redness and blistering.
• Combination light therapy. Combining UV light with other treatments such as retinoids frequently improves phototherapy's effectiveness. Combination therapies are often used after other phototherapy options are ineffective. Some doctors give UVB treatment in conjunction with coal tar, called the Goeckerman treatment. The two therapies together are more effective than either alone because coal tar makes skin more receptive to UVB light. Another method, the Ingram regimen, combines UVB therapy with a coal tar bath and an anthralin-salicylic acid paste that's left on your skin for several hours or overnight.
Oral or injected medications
If you have severe psoriasis or it's resistant to other types of treatment, your doctor may prescribe oral or injected drugs. Because of severe side effects, some of these medications are used for just brief periods of time and may be alternated with other forms of treatment.
• Retinoids. Related to vitamin A, this group of drugs may reduce the production of skin cells if you have severe psoriasis that doesn't respond to other therapies. Signs and symptoms usually return once therapy is discontinued, however. Side effects may include dryness of the skin and mucous membranes, itching and hair loss. And because retinoids such as acitretin (Soriatane) can cause severe birth defects, women must avoid pregnancy for at least three years after taking the medication.
• Methotrexate. Taken orally, methotrexate helps psoriasis by decreasing the production of skin cells and suppressing inflammation. It may also slow the progression of psoriatic arthritis in some people. Methotrexate is generally well tolerated in low doses, but may cause upset stomach, loss of appetite and fatigue. When used for long periods it can cause a number of serious side effects, including severe liver damage and decreased production of red and white blood cells and platelets.
• Cyclosporine. Cyclosporine suppresses the immune system and is similar to methotrexate in effectiveness. Like other immunosuppressant drugs, cyclosporine increases your risk of infection and other health problems, including cancer. Cyclosporine also makes you more susceptible to kidney problems and high blood pressure — the risk increases with higher dosages and long-term therapy.
• Hydroxyurea. This medication isn't as effective as cyclosporine or methotrexate, but unlike the stronger drugs it can be combined with phototherapy. Possible side effects include anemia and a decrease in white blood cells and platelets. It should not be taken by women who are pregnant or planning to become pregnant.
• Immunomodulator drugs (biologics). Several immunomodulator drugs are approved for the treatment of moderate to severe psoriasis. They include alefacept (Amevive), etanercept (Enbrel), infliximab (Remicade) and ustekinumab (Stelara). These drugs are given by intravenous infusion, intramuscular injection or subcutaneous injection and are usually used for people who have failed to respond to traditional therapy or who have associated psoriatic arthritis. Biologics work by blocking interactions between certain immune system cells. Although they're derived from natural sources rather than chemical ones, they must be used with caution because they have strong effects on the immune system and may cause life-threatening infections.
Although doctors choose treatments based on the type and severity of psoriasis and the areas of skin affected, the traditional approach is to start with the mildest treatments — topical creams and ultraviolet light therapy (phototherapy) — and then progress to stronger ones if necessary. The goal is to find the most effective way to slow cell turnover with the fewest possible side effects.
In spite of a wide range of options, effective treatment of psoriasis can be challenging. The disease is unpredictable, going through cycles of improvement and worsening seemingly at random. Effects of psoriasis treatments also can be unpredictable; what works well for one person might be ineffective for someone else. Your skin can also become resistant to various treatments over time, and the most potent psoriasis treatments can have serious side effects.
Talk to your doctor about your options, especially if you're not improving after using a particular treatment or if you're experiencing uncomfortable side effects. He or she can adjust your treatment plan or modify your approach to ensure the best possible control of your symptoms.