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Psoriasis (cont.)

Medical Treatment

Psoriasis is a chronic skin condition. Any approach to the treatment of this disease must be considered for the long term. Treatment regimens must be individualized according to age, sex, occupation, personal motivation, other health conditions, and available resources. Disease severity is defined not only by the number and extent of plaques present but also by the patient's perception and acceptance of the disease. Treatment must be designed with the patient's specific expectations in mind, rather than focusing on the extent of body surface area involved.

Many treatments exist for psoriasis. However, the construction of an effective therapeutic regimen is not necessarily complicated.

There are 3 basic types of treatments for psoriasis: (1) topical therapy (drugs used on the skin), (2) phototherapy (light therapy), and (3) systemic therapy (drugs taken into the body). All of these treatments may be used alone or in combination.

Topical agents: Medications applied directly to the skin are the first course of treatment options. The main topical treatments are corticosteroids, vitamin D-3 derivatives, coal tar, anthralin, or retinoids. There isn't one topical drug that is best for all people with psoriasis. Because each drug has specific adverse effects, it is common to rotate them. Sometimes drugs are combined with other drugs to make a preparation that is more helpful than an individual topical medication. For example, keratolytics (substances used to break down scales or excess skin cells) are often added to these preparations. Some drugs are incompatible with the active ingredients of these preparations. For example, salicylic acid (a component of aspirin) inactivates calcipotriene (form of vitamin D-3). On the other hand, drugs such as anthralin (tree bark extract) require addition of salicylic acid to work effectively.
Phototherapy (light therapy): The ultraviolet (UV) light from the sun slows the production of skin cells and reduces inflammation. Sunlight helps reduce psoriasis symptoms in some people. If psoriasis is widespread, as defined by more patches than can easily be counted, then artificial light therapy may be used. Resistance to topical treatment is another indication for light therapy. Proper facilities are required for the two main forms of light therapy. The medical light source in a physician's office is not the same as the light sources generally found in tanning salons.
- UV-B: Ultraviolet B (UV-B) light is used to treat psoriasis. UV-B is light with wavelengths of 290-320 nanometers (nm). (The visible light range is 400-700 nm.) UV-B therapy is usually combined with one or more topical treatments. UV-B phototherapy is extremely effective for treating moderate-to-severe plaque psoriasis. The major drawbacks of this therapy are the time commitment required for treatments and the accessibility of UV-B equipment.
  - The Goeckerman regimen uses coal tar followed by UV-B exposure and has been shown to cause remission in more than 80% of patients. Patients may complain of the strong odor when coal tar is added.
  - In the Ingram method, the drug anthralin is applied to the skin after a tar bath and UV-B treatment.
  - UV-B therapy is usually combined with the topical application of corticosteroids, calcipotriene (Dovonex), tazarotene (Tazorac), or creams or ointments that soothe and soften the skin.
- PUVA: PUVA is the therapy that combines a psoralen drug with ultraviolet A (UV-A) light therapy. Psoralen drugs make the skin more sensitive to light and the sun. Methoxsalen is a psoralen that is taken by mouth several hours before UV-A light therapy. UV-A is light with wavelengths of 320-400 nm. More than 85% of patients report relief of disease symptoms with 20-30 treatments. Therapy is usually given 2-3 times per week on an outpatient basis, with maintenance treatments every 2-4 weeks until remission. Adverse effects of PUVA therapy include nausea, itching, and burning. Long-term complications include increased risks of sensitivity to the sun, sunburn, skin cancer, and cataracts.

Systemic agents (drugs taken within the body): These drugs are generally started only after both topical treatment and phototherapy have failed. For generalized pustular psoriasis, systemic agents such as retinoids may be required from the beginning of treatment. This may be followed by PUVA treatment. For milder and chronic forms of pustular psoriasis, topical treatment or light treatment may be tried first. Systemic agents may be considered for very active psoriatic arthritis. People whose disease is disabling because of physical, psychological, social, or economic reasons may also be considered for systemic treatment.