Tinea spread through direct contact with infected humans or animals as well as contaminated fomites or vegetative matters. No age group is spared however there is a slight preponderance amongst post pubertal children and young adults probably due to physiological increase in sebum secretion secondary to androgen surge.
It has been seen that most of the time clinical features of tinea e.g. maculopapular scaly erethamatous lesions with or without central clearing considerably overlap with other dermatological conditions and pose a challenge to clinch the diagnosis. The following chart illustrates the in & out of tinea corporis in an easy to understand format.
So here we go..
Tinea Corporis -
Red scaly margin
Papules & pustules
◇Kerion common in children and associated with scalp abscess
◇ Majocchi granuloma common in females around hair & hair follicles of legs
◇ Tinea incognito - Steroid modified tinea mainly found over trunks, limbs etc.
■Clinical Microbiology Lab Diagnosis :
10% KOH for morphological identification of fungal etiology with seeding on SDA, PDA for culture confirmation with Fungal AST
■Differential Diagnosis of Tinea Corporis:
a) Discoid eczema ( nummular)
Less likely to have central clearing with more confluent scales
Erethematous, pruritic with erethamatous wheal
c) Contact Dermatitis
Well demarcated, erethematous lesion localised to the area of contact
d) Erethema marginatum
e) Atopic Dermatitis
Highly pruritic, lichenification in chronic lesions and also chronically relapsing
f) Plaque psoriasis
Annular , erethematous round or oval, pruritic plaques. Family History is positive. Nail pitting , arthritis , uveitis
g) Pityriasis rosea
Herald patch progressing to generalised rash
h) Secondary syphillis
Diffuse pattern, Symmetrical round or oval, pink -reddish macules
i) Lichen Planus
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