1. Moderate to Severe Psoriasis Slideshow
2. Psoriasis Quiz: Test Your Medical IQ
3. How Much Is Psoriasis Affecting Your Life?

Medical Author:

Gary W. Cole, MD, FAAD

Gary W. Cole, MD, FAAD

Dr. Cole is board certified in dermatology. He obtained his BA degree in bacteriology, his MA degree in microbiology, and his MD at the University of California, Los Angeles. He trained in dermatology at the University of Oregon, where he completed his residency.

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Medical Editor:

William C. Shiel Jr., MD, FACP, FACR

William C. Shiel Jr., MD, FACP, FACR

Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

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Acitretin (Soriatane) is used for severe psoriasis.

• How retinoids work: Retinoids are used to control psoriasis and reduce the redness of the skin. They can be used in combination with medically controlled ultraviolet phototherapy to minimize the dose of each.
• Who should not use these medications: Individuals who are allergic to retinoids, are pregnant, or are breastfeeding should not take retinoids.
• Use: Acitretin is in a capsule. It is usually taken once a day by mouth with food. Therapy is continued until plaques have decreased.
• Drug or food interactions: Acitretin increases methotrexate toxicity when both are used together. This medicine can interfere with oral contraceptives ("minipill"). Do not use alcohol while taking acitretin and for two months after stopping the medicine. Alcohol causes the drug to convert to a long-acting form and could prolong the risk of birth defects.
• Adverse effects: Women of childbearing age must use effective birth control measures. Birth control must be continued for at least three years after the woman stops taking acitretin because the drug stays in the body for a very long time and will hurt unborn babies. Caution must be used if the individual has kidney or liver problems. Contact the doctor immediately if you develop a rash or skin or vision changes.

Methoxsalen (Oxsoralen-Ultra) and trioxsalen (Trisoralen) are commonly prescribed psoralens. Psoralens are a class of drugs that make the skin more sensitive to light and the sun. Psoralens are used with ultraviolet light therapy. This therapy, called PUVA, uses a psoralen drug with ultraviolet A (UV-A) light to treat psoriasis when it covers a large area of the skin or is severe. More than 85% of patients report relief of disease symptoms with 20-30 treatments.

• How psoralens work: Psoralens have no effect unless combined with ultraviolet light therapy. They are used with the light therapy to slow skin-cell overproduction.
• Who should not use psoralens: Individuals with the following conditions should not take psoralens:
• Psoralen allergy
• History of skin cancer
• Photosensitivity diseases such as porphyria, lupus erythematosus, xeroderma pigmentosum, or albinism
• Inability to tolerate prolonged standing or heat, for example, in those with heart disease
• Pregnancy
• Children younger than age 12
• Use: Psoralens are taken by mouth 45 to 60 ,minutes prior to UVA exposure. Occasionally psoralens have been applied to the skin in creams, lotions, or bath soaks. This requires close medical monitoring due to the propensity to produce burns. Treatments frequency should not be shorter than 48 hours.
• Drug or food interactions: Other photosensitizing drugs, such as phenothiazines, bacteriostatic soaps, sulfonamides, tetracyclines, thiazides, or even perfumes may increase the skin's sensitivity to the sun or may cause other problems. Before taking psoralens, let the doctor know if any other medicine are being taken.
• Adverse effects: A doctor experienced with PUVA therapy should supervise the use of these medicines. Severe burns can occur from sunlight or the ultraviolet light while taking psoralens. These drugs cause sensitivity to sunlight and increase the risk of sunburn, skin cancer, and cataracts. After each treatment, avoid going out in the sun for at least 24 hours. Cover up with clothing and use sun block if the skin will be exposed to the sun. A certain type of sunglasses are recommended to protect the eyes after treatments. Treatment usually causes reddening of the skin for 24-48 hours. However, contact the doctor if severe redness, blisters, fever, or peeling occurs.

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