Herald patch followed by rash is characteristic of:
(b) Lichen planus
(c) Pityriasis rosea
ANS- (c) Pityriasis rosea
This is an acute, self-limiting exanthem that particularly affects young adults and occurs worldwide, with a slight female predominance.
It usually presents in spring and summer, although no infective agent has been identified and its aetiology is unknown.
It is characterised by the appearance of a ‘herald patch’, an oval lesion (1–2 cm) with a central pinkish (salmon-coloured) centre, a darker periphery and a characteristic collarette of scale.
It is followed 1–2 weeks later by a widespread papulosquamous eruption, which is typically arranged in a symmetrical ‘fir tree’ pattern on the trunk.
Individual lesions also have a collarette of scale. An inverse variant with flexural involvement can occur.
Mucosal involvement is rare.
There is a small risk of recurrence. Symptomatic relief can be achieved with emollients and mild topical glucocorticoids.
Post-inflammatory hyperpigmentation can supervene, particularly in darker skin types.