A 36 years old factory worker developed itchy annular scaly plaques in both groins. Application of a corticosteroid ointment led to temporary relief but the plaques continued to extend at the periphery.The most likely diagnosis is –
Erythema annulare centrifugam
Granuloma annulare
Annular lichen planus
Tenia cruris
In this question :-


Annular lesion in groins
Scaly
Itching
Extending peripherially


All suggest the diagnosis of dermatophyte infection.
Dermatophyte infection of groin is known as T. cruris.