Ringworm is a fungal infection of the skin. It is also known as tinea and dermatophytosis. Fungal infections have specific names depending on the area they affect:
- Tinea capitis refers to ringworm affecting the scalp (caput meaning head)
- Tinea pedis refers to ringworm affecting the feet, also known as athletes foot (pedis meaning foot)
- Tinea cruris refers to ringworm of the groin (cruris meaning leg)
- Tinea corporis refers to ringworm on the body (corporis meaning body)
- Onychomycosis refers to a fungal nail infection
The most common type of fungus that causes ringworm is called trichophyton. It is spread through contact with infected individuals, animals or soil.
Ringworm presents as an itchy rash that is erythematous, scaly and well demarcated. There is often one or several rings or circular shaped areas that spread outwards, with a well demarcated edge. The edge is more prominent and red and the area in the centre is more faint in colour.
Tinea capitis can present with well demarcated hair loss. There will also be itching, dryness and erythema of the scalp. This is more common in children than adults.
Tinea pedis (athletes foot) presents with white or red, flaky, cracked, itchy patches between the toes. The skin may split and bleed. This is often the result of sharing changing rooms with someone that has athletes foot and is more likely to occur when feet are sweaty and damp for prolonged periods.
Onychomycosis (fungal nail infections) presents with thickened, discoloured and deformed nails.
TOM TIP: Check the toenails in someone presenting with ringworm, you may find they have a fungal nail infection that has spread to the skin.
The diagnosis is usually clinical. This is supported by a good response to anti fungal medications. It is possible to scrape some of the scales off and send them for microscopy and culture to identify the causative organism and confirm the diagnosis.
Treatment of ringworm is with anti-fungal medications:
- Anti-fungal creams such as clotrimazole and miconazole
- Anti-fungal shampoo such as ketoconazole for tinea capitis
- Oral anti-fungal medications such as fluconazole, griseofulvin and itraconazole
Fungal nail infections can be treated with amorolfine nail lacquer for 6 – 12 months. Resistant cases may need oral terbinafine, however the patient will need their LFTs monitoring before and whilst taking this.
A mild topical steroid can help settle the inflammation and itching. A common combination is miconazole 2% and hydrocortisone 1% cream (Daktacort).
Simple advice should be given to help recovery, prevent spread and avoid recurrence. Fungal infections grow best in warm, moist areas. Advise includes:
- Wear loose breathable clothing
- Keep the affected area clean and dry
- Avoid sharing towels, clothes and bedding
- Use a separate towel for the feet with tinea pedis
- Avoid scratching and spreading to other areas
- Wear clean dry socks every day
Tinea incognito refers to a more extensive and less well recognised fungal skin infection that results from the use of steroids to treat an initial fungal infection.
This often occurs when the initial presentation of ringworm was misdiagnosed as dermatitis and a topical steroid was prescribed. The steroid improves the itching and inflammation but accelerates the growth of the fungal infection by dampening the immune response in the local area. When the steroid is stopped the itchy rash caused by the fungus returns and is much worse than previously. It may be less recognisable as ringworm due to a less well-demarcated border and fewer scales, giving rise to the incognito name.
Last updated January 2020