Psoriasis epidemiology

Christophers E. Psoriasis—epidemiology and clinical spectrum. Qin Exp Dermatol 2001 26 314-320. 

A recent review of epidemiological studies covering 24 specific autoimmune diseases estimated that approximately 3% of the population in the United States suffers from an autoimmune disease (Jacobson et al., 1997). This estimate is likely to be low, as for many diseases our knowledge of basic epidemiology is quite limited or based on studies conducted 30 or more years ago, and some diseases (e.g. psoriasis) were not included in this summary. A revised estimate of the prevalence of autoimmune diseases presented in a recent report of the United States National Institutes of Health (2000) is 5-8%. Comparable figures for other countries are not available. 

In an epidemiological study of 1253 psoriatic patients, Melski et al. (1983) found that one-third of the study population had a history of Koebner response at sites of physical trauma. These patients were also found to be associated with earlier onset of psoriasis in life and a tendency to flare despite various treatment options. Apart from the limitations of this study, the authors believed that there is indeed a subset of psoriatic patients, in which Koebner phenomenon may be an important marker. Thus, it is important to identify psoriatic patients and discourage them from engaging in jobs in which they will be subject to excessive trauma. 

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