Drug which is topically used in Tinea cruris infection is:

Ans: c (Terbinafine) Ref: Harrison, 16th ed, p. 293, Tripathi, 5th ed, p. 723Tinea cruris is a dermatophytic infection of groin.Terbinafine is an orally and topically active drug against dermatophytes & Candida.Terbinafine is fungicidal, in contrast to Azoles which are fungistatic.Terbinafine acts as a non-competitive inhibitor of squalene epoxidase, an early step in the biosynthesis by fungi.Diagnostic points of Tinea crurisBilateralAnnular scaly plaques in the groin.Presence of itchingUnresponsiveness to steroids.Peripheral extension with centr al clearing.Drugs used for moderately severe ringworm involving scalp, beard, nailbedSystemic - GriseofulvinTopical - Itraconazole, Terbinafme.Griseofulvin is the drug of choice for dermatophytosis.Duration of treatment with GriseofulvinSkin: 3wksPalms & soles: 4-6 wksFingernails: 4-6 monthsToe nails: 8-12 monthsDermatophytes are fungi that infect skin, hair and nails. They affect stratum comeum.It includes-Epidermophyton (no hair involvement)-Microsporum (no nail involvement)-Trichophyton.Note:Most common cause of Tinea cruis in India - Trichophyton rubrum.Most common cause of Tinea cruris in western countries -Epidermophyton flocossum.Tinea versicolor in KOH mount shows sphaghetti & meatball appearance.Favus is a chronic type of ringworm in which dense crusts develop in the hair follicles, which lead to alopecia and scarring.Scalp infection sometimes produce severe boggy lesions with marked inflammatory reaction called 'kerion'. Trichophyton tonsurans is mainly associated with kerion.