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What is A 40-year-old woman presented with 8-month history of erythema and swelling of the periorbital region & papules & plaques an the dorsolateral aspect of forearms & knuckles with ragged cuticles. There was no muscle weakness. The most likely diagnosis is – and explain in detail?
This woman has:-


Erythema and swelling to periorbital region → Heliotrope erythema.
Papules and plaques on the dorsolateral aspect of knuckle & forearms → Gottron's papule.


Diagnosis is Dermatomyositis.