Makindo Medical Notes

🦠 Tinea corporis (ringworm of the body) is a superficial fungal infection caused by dermatophytes. It commonly affects the arms, legs, and trunk but can occur anywhere on the body. Named "ringworm" for its classic ring-shaped lesions, though no worm is involved. It is one of the most frequent dermatology presentations in GP and A&E clinics in the UK.

🔎 Etiology

Caused by dermatophyte fungi from 3 main genera:

• Trichophyton rubrum – most common worldwide 🌍.
• Trichophyton mentagrophytes – often zoonotic.
• Microsporum canis – linked to cats & dogs 🐱🐶.

⚡ Risk Factors

• 🌡️ Warm & humid climates (sports, gyms, tropical travel).
• 👨‍👩‍👧 Close contact with infected people or pets.
• 🧦 Shared towels, clothes, mats, or sports gear.
• 💦 Hyperhidrosis (excess sweating).
• 🛡️ Immunosuppression (HIV, diabetes, steroids).

🩺 Clinical Presentation

• Lesions:
  • Annular, scaly, red plaque with central clearing ➝ “ring” 🔴.
  • Active advancing edge with scaling & itch.
  • Multiple lesions may merge into large patches.
• Symptoms:
  • Pruritus (itch) is the hallmark 🚨.
  • Mild burning or irritation in some cases.
• Common Sites: Arms, legs, trunk, chest, back, face.

🖼️ Typical annular lesions:

🧾 Diagnosis

Usually clinical; investigations if atypical or recurrent:

• 👀 Clinical Exam: Ring-shaped, scaly plaques.
• 🔬 KOH prep: Hyphae visible in scrapings.
• 🧫 Culture: Useful for resistant/recurrent cases.
• 💡 Wood’s Lamp: Microsporum fluoresces green.

🔀 Differential Diagnosis

• Psoriasis 🧴
• Atopic eczema 🤧
• Nummular eczema
• Pityriasis rosea 🌹
• Granuloma annulare
• Cutaneous lupus erythematosus

💊 Treatment

Choice depends on severity, extent, and patient comorbidity:

• Topical antifungals (first-line, localised):
  • Azoles: clotrimazole, miconazole, ketoconazole.
  • Allylamines: terbinafine (often most effective).
  • Applied BID for 2–4 weeks ⏳.
• Oral antifungals (extensive/resistant):
  • Terbinafine 250mg OD 2–4 weeks.
  • Itraconazole 100–200mg OD 2–4 weeks.
  • Griseofulvin 500–1000mg OD 4–6 weeks (children, scalp involvement).
• Supportive advice: Hygiene, dry skin, avoid sharing items.

🛡️ Prevention

• Avoid contact with infected pets/people.
• No sharing towels/clothes/gym equipment.
• Keep skin clean & dry; wear loose cotton clothing 👕.
• Use antifungal powder if prone to recurrences.

⚠️ Complications

• 📈 Spread to other areas / household contacts.
• 🦠 Secondary bacterial infection from scratching.
• 🎭 Tinea incognito: Steroid creams mask & worsen infection.

📊 Prognosis

✅ With appropriate antifungals, most cases clear in 2–4 weeks. ♻️ Relapse is common if underlying risk factors (moisture, pets, poor hygiene) are not addressed. Immunosuppressed patients may require longer systemic therapy.

📌 Summary

Tinea corporis = itchy, annular fungal infection of the skin. 🔑 Diagnosis: clinical ± KOH prep. 💊 Treatment: topical antifungals ➝ oral if widespread. 🛡️ Prevention: hygiene, avoid contact & sharing. 🌟 Prognosis: excellent with treatment, but recurrence common.