Clinical features

Presentation is with fawn-coloured, large (around 2-10 cm in diameter), slightly raised, oval scaly patches which typically develop on the limbs and trunk - commonly known as an initial 'herald' lesion. Often there is a collarette of scale present at the margin in some lesions (1).

After a few days to few weeks, smaller (5-10 mm in diameter) secondary lesions develops in the trunk (extremities are less frequently involved).

• these are salmon colored, ovoid, raised lesions with a collarette of scale as well.
• may last for 4 to 10 weeks (1,2)

The longitudinal diameters of the small secondary oval lesions are parallel to the lines of Langer. On the back, lesions tend to show the distribution in the pattern of the branches of a fir tree or “Christmas tree” (1).

There may be mild to moderate itching associated with the lesions.

Pityriasis rosea may present in different other forms

• inverse form – extremities are involved but the trunks is spared
• localized form – less common
• Gigantean (larger and fewer lesions), pustular, purpuric, or vesicular pityriasis rosea – on rare occasions
• Sometimes may present without herald patches (1)

Reference:

• (1) Stulberg DL, Wolfrey J. Pityriasis Rosea. AFP 2004;69(1)
• (2) Amer A et al. The Natural History of Pityriasis Rosea in Black American Children. Arch Pediatr Adolesc Med. 2007;161(5):503-506