Temporal case clustering in pityriasis rosea: a regression analysis on 1379 patients in Minnesota, kuwait, and diyarbakir, Turkey.

OBJECTIVE

To detect temporal case clustering in patients with pityriasis rosea in different geographic locations.

DESIGN

Regression analysis of dates on which 1379 patients were diagnosed as having pityriasis rosea in 3 different geographic locations. The control data consisted of dates of diagnosis of patients with psoriasis in the same settings.

SETTING

Dermatology clinics in Kuwait, Minnesota, and Diyarbakir, Turkey.Patients Patients with pityriasis rosea and psoriasis seeking care in the clinics.

RESULTS

Three significant positive clusters (P = .005, P =.001, and P =.01, respectively) and 1 significant negative cluster (P<.001) were detected in these series of patients. No cluster was detected in 2 corresponding series of patients with psoriasis in Kuwait and Turkey.

CONCLUSION

Temporal case clustering exists in pityriasis rosea.