Psoriasis - Dictionary Definition and Overview

• Guttate Psoriasis: Drop-like lesions appear on the trunk, limbs, and scalp. Guttate psoriasis may be triggered by viral respiratory infections or certain bacterial (streptococcal) infections.
• Pustular Psoriasis: Blisters of noninfectious pus appear on the skin. Attacks of pustular psoriasis may be triggered by medications, sunlight, infections, pregnancy, perspiration, emotional stress, or exposure to certain chemicals.
• Inverse Psoriasis: Large, dry, smooth, vividly red plaques occur in the folds of skin near the genitals, under the breasts, or in the armpits. Inverse psoriasis is related to increased sensitivity to friction and sweating.
• Erythrodermic Psoriasis: Widespread reddening and scaling of the skin is often accompanied by itching or pain. Erythrodermic psoriasis may be precipitated by severe sunburn, use of oral steroids (such as cortisone), or a drug-related rash.

• Sunlight Daily, regular, short doses of sunlight without burning clears psoriasis in many people with the disease. However, exposure to sunlight is not recommended for those undergoing ultraviolet light treatments or using certain topical treatments, such as coal tar, which make the skin extra sensitive to the sun's effects.
• Corticosteroids Available in different strengths, corticosteroids (cortisone) are usually applied twice each day. Short-term treatment is often effective. If less than 10 percent of the body's skin is involved, some doctors will begin treatment with a high-potency corticosteroid ointment (for example, Diprolene*, Temovate, Ultravate, or Psorcon). High-potency steroids may also be used for treatment-resistant plaques, particularly those on the hands or feet. Long-term use or overuse of high-potency steroids can lead to thinning of skin, internal side effects, resistance to the treatment's benefits, and worsening of the psoriasis. Medium-potency corticosteroids may be used on the torso or limbs; low-potency preparations are used on delicate skin areas.
• Calcipotriene This drug is a synthetic form of vitamin D3. (This is not the same as vitamin D supplements.) Application of calcipotriene ointment (for example, Dovonex) twice daily controls the excessive production of skin cells in psoriasis. Because calcipotriene can irritate the skin, it is not recommended for the face or genitals. After 4 months of treatment, about 60 percent of patients have a good to excellent response to calcipotriene. The safety of using the drug for psoriasis affecting more than 20 percent of the body's skin is unknown; use on widespread areas of skin may raise the amount of calcium in the body to unhealthy levels.
• Coal tar Coal tar may be applied directly to the skin, used in a bath solution, or used as a shampoo for the scalp. It is available in different strengths, but the most potent form may be irritating. Because coal tar makes skin more sensitive to ultraviolet (UV) light, it is sometimes combined with ultraviolet B (UVB) phototherapy. Compared with steroids, coal tar has fewer side effects but is messy and less effective and thus is not popular with many patients. Other drawbacks include its failure to provide long-term help for most patients, its strong odor, and its tendency to stain skin or clothing.
• Anthralin Doctors sometimes use a 15- to 30-minute application of anthralin ointment, cream, or paste to treat chronic psoriasis lesions. However, this treatment often fails to adequately clear lesions, it irritates the skin, and it stains skin and clothing brown or purple. In addition, anthralin is unsuitable for acute or actively inflamed eruptions.
• Salicylic acid Used to remove scales, salicylic acid is usually more effective when combined with topical steroids, anthralin, or coal tar.
• Bath solutions People with psoriasis may find that bathing in water with an oil added, then applying a moisturizer, can soothe the skin. Scales can be removed and itching reduced by soaking 15 minutes in water containing a tar solution, oiled oatmeal, Epsom salts, or Dead Sea salts.
• Moisturizers When applied regularly over a long period, moisturizers have a cosmetic and soothing effect. Preparations that are thick and greasy usually work best because they lock water into the skin.

• UVB Phototherapy Artificial sources of UVB light are similar to sunlight. Some physicians will start with UVB treatments instead of topical agents. UVB phototherapy also is used to treat widespread psoriasis and lesions that resist topical treatment. This type of phototherapy is normally administered in a doctor's office by using a light panel or light box, although with a doctor's guidance, some patients can use UVB light boxes at home. UVB phototherapy also may be combined with other treatments. One combined therapy program, referred to as the Ingram regime, involves a coal tar bath, UVB phototherapy, and application of an anthralin-salicylic acid paste, which is left on the skin for 6 to 24 hours. A similar regime, the Goeckerman treatment, involves application of coal tar ointment and UVB phototherapy.
• PUVA This treatment combines oral or topical administration of a medicine called psoralen with exposure to ultraviolet A (UVA) light. Psoralen makes the body more sensitive to UVA light. PUVA is normally used when more than 10 percent of the body's skin is affected or when rapid clearing is required because the disease interferes with a person's occupation (for example, when a model's face or a carpenter's hands are affected by psoriasis). Compared with daily UVB treatment, PUVA treatment taken two to three times per week clears psoriasis more consistently but less quickly. However, it is associated with more side effects, including nausea, headache, fatigue, burning, and itching. Long-term treatment is associated with irregular skin pigmentation. Researchers have found that PUVA is effective and relatively safe when combined with some oral medications (retinoids and hydroxyurea) but appears to be associated with skin cancer when combined with other oral medications (for example, methotrexate or cyclosporine). In rare cases, patients who must travel long distances for PUVA treatments may, with a physician's close supervision, be taught to administer this treatment at home.

• Retinoids These drugs are derived from vitamin A and include etretinate (Tegison) and isotretinoin (Accutane). Etretinate is most effective against pustular and erythrodermic psoriasis. Isotretinoin is also helpful against pustular psoriasis. Both drugs can cause birth defects and are not recommended for women of childbearing age. At high doses, etretinate can affect liver function. Therefore it is often combined with UVB phototherapy or PUVA so that a lower, less toxic, dose can be taken.
• Methotrexate This treatment, which can be taken by pill or injection, slows down cell production and suppresses the immune system that is causing the skin inflammation. Patients taking methotrexate must be closely monitored because this drug can cause liver damage or decrease the production of oxygen-carrying red blood cells, infection-fighting white blood cells, and clot- enhancing platelets. As a precaution, doctors do not prescribe the drug for people with long-term liver disease or anemia. Also, methotrexate should not be used by pregnant women, by women who are planning to get pregnant, or by their male partners.
• Hydroxyurea (Hydrea) Compared with methotrexate, hydroxyurea is less toxic but also less effective. Hydroxyurea is sometimes combined with PUVA or retinoids. Possible side effects include anemia and a decrease in white blood cells and platelets. Like methotrexate, hydroxyurea must be avoided by pregnant women or those who are planning to get pregnant.
• Antibiotics Although seldom used in routine treatment, antibiotics may be employed when an infection such as streptococcus has triggered the outbreak of psoriasis, as in certain cases of guttate psoriasis.
• TNF-Blockade New drugs available for the treatment of persisting psoriasis are called TNF-Blockers. TNF is a chemical messenger that calls to cells of inflammation to come to a certain area of the body. The skin of patients with psoriasis is releasing TNF at the sites of inflammation. Medications, such as etanercept (Enbrel) and infliximab (Remicade), can block the action of TNF, thereby stopping the inflammation process, and effectively quieting the psoriasis.

Psoriasis At A Glance

• Psoriasis is a chronic (long-lasting) skin disease characterized by scaling and inflammation, affecting almost 2% of the US population.

• When psoriasis develops, patches of skin thicken, redden, and become covered with silvery scales; these patches are also known as plaques.

• Psoriasis most often occurs on the elbows, knees, scalp, lower back, face, palms, and soles of the feet; diagnosis may be difficult because psoriasis often looks like other skin diseases.

• Doctors generally treat psoriasis in steps according to the severity of the disease or responsiveness to initial treatments. This is sometimes called the "1-2-3" approach.