Ringworm

Definition
Ringworm, also known as dermatophytosis or tinea, is a superficial fungal infection of the skin, hair, or nails caused by dermatophyte fungi. Despite its name, it is not caused by a worm. The term “ringworm” comes from the ring-shaped rash commonly seen in skin infections.

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Causative Organisms

• Trichophyton species (most common — e.g., T. rubrum, T. tonsurans)

• Microsporum species (e.g., M. canis)

• Epidermophyton floccosum

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Transmission

• Direct skin-to-skin contact with infected person or animal

• Indirect contact via contaminated items (towels, bedding, clothing, combs)

• Contact with contaminated soil

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Types & Locations

• Tinea corporis – body skin

• Tinea capitis – scalp

• Tinea pedis – feet (athlete’s foot)

• Tinea cruris – groin (jock itch)

• Tinea unguium / onychomycosis – nails

• Tinea faciei – face

• Tinea manuum – hands

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Clinical Features

• Skin: Circular, scaly, red patches with raised edges and central clearing

• Scalp: Patchy hair loss, scaling, sometimes kerion (boggy swelling with pus)

• Feet: Itching, scaling, fissures, maceration between toes

• Groin: Red, itchy rash with sharply defined edges

• Nails: Thickened, brittle, discoloured nails

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Diagnosis

• Clinical examination based on lesion appearance

• Confirmation with:

  • KOH preparation – microscopic fungal hyphae

  • Fungal culture – to identify species

  • Wood’s lamp – Microsporum may fluoresce green

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Treatment

General Measures

• Keep affected area clean and dry

• Avoid sharing towels, clothing, or hairbrushes

• Treat infected pets if identified as source

Topical Antifungals (for skin infections, mild cases)

• Clotrimazole 1% cream: Apply twice daily for at least 2–4 weeks, continue 1–2 weeks after symptoms resolve

• Miconazole 2% cream: Twice daily

• Terbinafine 1% cream: Once or twice daily for 1–2 weeks

Oral Antifungals (for scalp, nail, severe, or widespread infection)

• Terbinafine: Adults — 250 mg once daily (2–4 weeks for skin; 6–12 weeks for nails; 4–6 weeks for scalp)

• Itraconazole: Adults — 100 mg once daily for 15 days or 200 mg daily for 7 days (pulse therapy for nails)

• Griseofulvin: Children — 10–20 mg/kg/day for 4–6 weeks (especially for tinea capitis)

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Complications

• Secondary bacterial infection

• Chronic or recurrent infection if not treated completely

• Permanent hair loss in severe scalp infection (kerion)

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Quick-Reference Clinical Chart — Ringworm

Feature	Details
Definition	Superficial fungal infection of skin, hair, or nails by dermatophytes
Common Species	Trichophyton, Microsporum, Epidermophyton
Transmission	Direct contact with infected humans, animals, objects, soil
Key Symptoms	Itchy, ring-shaped rash; scaling; possible hair loss or nail changes
Diagnosis	Clinical, KOH microscopy, fungal culture
Topical Treatment	Clotrimazole, miconazole, terbinafine
Oral Treatment	Terbinafine, itraconazole, griseofulvin (dose depends on site and patient age)
Prevention	Keep skin dry, avoid sharing personal items, treat pets
Prognosis	Excellent with full treatment; recurrence possible if risk factors persist