Brief Answer:
PR, ps, and PLEVA mimic each other. Biopsy helps.

Detailed Answer:
Hi,
Thanks for writing to us.
Pityriasis rosea is characterised by small red lesions with scaling at margin. It is preceded by a herald patch( a big similar patch). lesions are usually discrete along ribs.mIt is a self limiting condition

Psoriasis can present as red lesions covered with silvery adherent scales. Scalp involvement, nail involvement may be seen.

Mucha haberman disease or PLEVA ( chicken pox like lesions. There is another form known as pityriasis lichenoids chronica which may mimic PR or psoriasis.

So sometimes when lesions cannot be diagnosed clinically. Skin biopsy is advised with differentials and based on histopathology report diagnosis is confirmed.

I would like you to attach detailed reports and image of the lesions so that we may continue the discussion regarding most probable cause in your case.

Hoping to hear from you soon.
Take care

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