Answer

Answer to last month's Clinical Quiz

Question:
This 40 years old housewife presented with a mildly pruritic erythematous rash over the trunk for three weeks. There was peripheral scaling of individual lesion. The extremities were spared. She was otherwise well. There was a preceding upper respiratory tract infection about three weeks ago. The rash subsequently subsided after two months. There was no history of venereal exposure.

Answer:
D. Pityriasis rosea

Pityriasis rosea usually presents with an acute onset of skin rash over the trunk and proximal parts of limbs, with no or minimal systemic upset. It is more common in children and young adults. The aetiology is unknown, but is possibly related to infective agent. In the early stage, the characteristic lesion is the herald patch, which often may be missed. The typical lesions consist of non- or mildly-pruritic oval macular lesions with peripheral collarette of scales, arranged along the line of cleavage in a "Christmas tree" appearance. The face can also be affected especially in children. The palms are rarely involved and this is a useful feature to distinguish from secondary syphilis, which is an important differential diagnosis in adults. Individual lesions often subside within 3-6 weeks, and the whole course usually subsides within three months. Diagnosis of pityriasis rosea with duration longer than that should be revised. The disease is self-limiting and recurrence is very uncommon. Treatment is usually symptomatic with moderately potent topical steroid.