Psoriasis is a chronic skin condition that may worsen and improve in cycles. 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 only 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 three 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 D3 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 inactivates calcipotriene (form of vitamin D3). On the other hand, drugs such as anthralin (tree bark extract) require the 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 many people. If psoriasis is so widespread that topical therapy is impractical, then artificial light therapy may be used. 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, which are
of limited use for psoriasis. It must be remembered that all UV radiation has a potential to cause mutations and skin cancers. Although the incubation period for these skin cancers is quite long, UV exposures should be carefully monitored.
UV-B: Ultraviolet B (UV-B) light is used to treat psoriasis. UV-B is light with wavelengths of 290-320 nanometers (nm). Within the last 10 years, a new form of UV therapy called narrow-band UV-B (NBUVB) has become available which seems to be very effective with less burning potential than conventional broadband UV-B. It presumably contains the most therapeutic wavelengths and avoids the more toxic ones. (The visible light range is 400 nm-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 often complain of the strong odor when coal tar is added,
and it stains clothing, towels, and sheets.
UV-B therapy can be combined with the topical application of corticosteroids, calcipotriene (Dovonex), tazarotene (Tazorac), or creams or ointments that soothe and soften the skin.
Laser therapy (Excimer laser): A laser that produces UV-B light in the same wavelength as full body phototherapy units can target smaller areas of psoriasis without affecting the surrounding skin. Because the light treats only the psoriasis plaques, a strong dose of light can be used, which may be useful to treat a stubborn plaque of psoriasis, such as on the scalp, feet, or hands. This is an impractical treatment for psoriasis that covers a large area and, like other forms of phototherapy, requires regular visits over several months.
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. Methoxypsoralen is a psoralen that is taken by mouth an hour before UV-A light therapy. UV-A contains light with wavelengths of 320 nm-400 nm. More than 85% of patients report relief of disease symptoms with 20-30 treatments. Therapy is usually given two to three times per week on an outpatient basis, with maintenance treatments every two to four 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. Availability of the psoralen medication in the United States has been a problem, with lack of availability of the medication periodically extending for weeks or months at a time. This has discouraged its use.
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.
Medically Reviewed by a Doctor on 6/5/2015
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