Pityriasis rosea in Sri Lanka

Though pityriasis rosea is a common disorder, no study has been reported of its prevalence and clinical features and possible precipitating factors from Sri Lanka.

All new patients presenting with features of pityriasis rosea to the skin clinic of the General Hospital, Colombo, in the period between May and September 1994 were studied. Of the 102 patients studied, 85 patients who satisfied the set criteria were included in the study. This constituted 2.68% of the new patients attending the skin clinic. There were 44 males and 41 females, with ages ranging from 1.5 years to 50 years. 86.2% were between the ages of 11 and 30 years. 37 (43.5%) reported infections in the preceding three months, 31 of these being in the upper respiratory tract. A herald patch was seen in 57 (67.1%) of the patients, with the trunk being the site in 23. The average interval between the herald patch and the onset of the generalized eruption was 5.8 days. In 80 (94%), the generalized eruption occurred on the trunk. The classical "fir tree" pattern was seen in only 35 (41.2%) of the patients. Atypical morphological patterns were seen in 42 (49%) of the patients, in most in addition to the typical pattern. The average duration of the rash was for a period of 6.7 weeks.