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What Is Severe Psoriasis?

Impact on a patient’s quality of life is more important than skin area in determining disease severity.

All patients with psoriasis would like to rid themselves of it. Some have widespread disease; others have psoriasis only on the scalp or only on the elbows and knees and not elsewhere. Others have a single plaque on the penis. Who has the most severe disease? According to the FDA, severe disease is defined by plaques affecting more than 20% of the total body surface area (BSA). But who is really more severely affected — a patient with psoriasis over 25% of his body who goes about his day undisturbed, in short sleeves and shorts, or a patient with 1% involvement who hides at home and refuses social invitations in shame? In clinical practice, dermatologists routinely take into account the impact of psoriasis on quality of life in determining severity.

Now, a group of experts has validated this concept. In a consensus report, they conclude that physical and mental disabilities should be considered when judging psoriasis severity. Psoriasis affects physical, emotional, social, sexual, and financial aspects of life. Affected patients have trouble sleeping, sitting, walking, and using their hands. They are sad, embarrassed, and burdened with shame. They lose time and income from work and spend time and income on treatments. They don’t date. These patients may need "aggressive therapies," even if only small portions of their skin have psoriasis.

Thus, the consensus group divides psoriatic patients into two "tiers" based on the need for local therapy versus systemic treatments and phototherapy. Candidates for local therapy often have psoriasis involving less than 5% of their BSA. However, some patients affected over less than 5% of their BSA should be candidates for systemic therapy, phototherapy, or both, because of difficulties related to location, coexisting psoriatic arthritis, or impaired physical or mental functioning.

Comment: Psoriasis is not a cosmetic disease. Although the subjectivity involved in placing a patient in one tier or the other may make third-party carriers nervous, this "therapy-based" division of patients reflects the actual circumstances by which dermatologists make treatment decisions and the way patients want to be treated.

— Mark V. Dahl, MD

Published in Journal Watch Dermatology March 16, 2007

Citation(s):

Pariser DM et al. National Psoriasis Foundation clinical consensus on disease severity. Arch Dermatol 2007 Feb; 143:239-42.

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