Fungal Skin Infection (Tinea)
Fungal skin infections, also known as tinea or ringworm, are superficial dermatophyte infections affecting keratinised tissues such as the skin, scalp, hair and feet.
This updated UKMLA guide to fungal skin infection is based on NICE CKS, which covers tinea capitis, tinea corporis, tinea cruris and tinea pedis, including risk factors, diagnosis, and management.
Management Overview
The choice of antifungal across the 3 fungal skin infections is similar but not the same:
- Scalp infection
- 1st line: oral antifungal (terbinafine or griseofulvin)
- Body + groin + foot (Athlete’s foot) infection shares the same management:
- 1st line: topical antifungal (terbinafine or imidazole)
- Oral antifungal (1st line: terbinafine) reserved for severe / extensive disease
Scalp Infection (Tinea Capitis)
Fungal infection of the scalp is also known as tinea capitis or scalp ringworm.
Causes and Risk Factors
Most commonly caused by a dermatophyte:
- Trichophyton tonsurans (caused by human-to-human spread)
- Microsporum canis (caused by animal-to-human spread)
Risk factors:
- Most commonly affects pre-pubertal children (peak incidence 3-7 y/o)
- More common in Afro-Caribbean children
- Hot, humid climates
Clinical Features
Non-inflammatory involvement is more common:
- Scaling and itching of the scalp
- Patchy / circular alopecia (hair loss)
- Singular or multiple
- Typically non-scarring
- Usually asymmetrical
Inflammatory involvement is less common but more severe:
- Erythema, scattered pustules, crusting
- Kerion (a painful pustular boggy mass)
- Permanent, scarring alopecia
- Lymphadenopathy (usually post-auricular and cervical)
Secondary bacterial infection can also occur.
Investigation and Diagnosis
Dermoscopy is a helpful non-invasive method to help diagnose tinea
Test of choice: skin and hair samples for fungal microscopy and culture
Management
Referral Criteria
- Suspected kerion → urgent referral
- Unsuccessful treatment in primary care
- Severe / extensive / recurrent infection
- Immunocompromised patients
General Management / Self-Care Advice
Self-management:
- Soften any surface crusts (e.g. moistened dressings), then gently tease away
Measures to prevent spread and transmission:
- Discard / disinfect objects that can transmit fungal spores (e.g. hats, scarves, hairbrushes, combs, pillows, blankets, scissors)
- Do not share towels, and wash frequently
- If household pet is the suspected source, assess and treat by a vet
Antifungal Treatment
| Indications to treat | Practically speaking, almost all patients require treatment
Specific indications to treat (ANY):
|
| Choice of antifungal | 1st line: oral antifungal (terbinafine or griseofulvin) +/- topical antifungal (e.g. ketoconazole shampoo, imidazole cream)
2nd line antifungal: oral itraconazole |
| Follow up | Review the patient 4-8 weeks after completing oral antifungal therapy.
If signs of persistent / recurrent infection, or hair regrowth do not occur → repeat skin and hair sampling for fungal microscopy and culture. |
Body and Groin Infection (Tinea Corporis and Tinea Cruris)
Fungal infection of the body is also known as ‘tinea corporis’ or ‘ringworm’, and fungal infection of the groin is also known as ‘tinea cruris’ or ‘jock itch’
Causes and Risk Factors
Fungal body infection is usually caused by the dermatophyte Trichophyton rubrum or Trichophyton interdigitale.
Fungal groin infection is usually caused by autoinoculation from dermatophyte infection of the hands, feet, or nails caused by Trichophyton rubrum, Trichophyton interdigitale.
Risk factors:
- Hot, humid climates
- Working in high-temperature environments
- Tight-fitting clothing
- Obesity
- Hyperhidrosis
- Immunocompromised
Clinical Features
| Body infection (tinea corporis) | Affected areas will be itchy and scaly
Appearance:
More rarely, numerous overlapping concentric circles (tinea imbricate) or herpetiform subcorneal vesicles or pustules (bullous tinea corporis) |
| Groin infection (tinea cruris) | Most commonly affect the inguinal folds and proximal medial thigh
Affected areas will be itchy and scaly Appearance:
|
Tinea incognito
Occurs due to inappropriate use of topical corticosteroid (often due to misdiagnosis or self-medication), leading to extensive spread of fungal infection and change in morphology of the lesion
Possible features:
- Bizarre-shaped lesions
- Loss or modification of the active erythematous edge
- Loss of central clearing with eczematous areas within lesions
- Appearance of double edges or multiple rings
AVOID using topical corticosteroids in tinea.
Investigation and Diagnosis
Test of choice: skin samples for fungal microscopy and culture
Management
General Management / Self-Care Advice
Self management:
- Wear loose-fitting clothes made of cotton or material designed to keep moisture away from the skin
- Wash affected skin daily + dry the skin after washing (esp. in the skin folds)
- Avoid scratching affected skin (as this may spread the infection to other sites)
Measures to prevent spread and transmission:
- Do not share towels, and wash frequently
- Wash clothes and bed linen frequently
If a child is affected, it is NOT necessary to exclude them from school or nursery
Antifungal Treatment
| Mild AND non-extensive disease | 1st line: topical antifungal cream
Consider a mildly potent topical corticosteroid (e.g. hydrocortisone 1%) if there is associated marked inflammation |
| Severe OR extensive disease | Consider oral antifungal
|
In children, 1st line is topical imidazole.
Topical terbinafine cream is NOT licensed in those <12 y/o
Foot Infection (Tinea Pedis)
Fungal infection of the foot is also known as ‘athlete’s foot’ or ‘tinea pedis’.
Causes and Risk Factors
Interdigital tinea pedis is most commonly caused by the dermatophyte Trichophyton rubrum
Risk factors:
- Hot, humid climates
- Working in high-temperature environments
- Wearing occlusive footwear (e.g. athletes, miners, soldiers)
- Hyperhidrosis
- Walking on contaminated floor surfaces (e.g. communal shower facilities, swimming pools, saunas)
- Immunocompromised
The prevalence of fungal foot infection increases with age (peak: 31-60 y/o) and is more common in males
Clinical Features
Typically causes scaly, itchy, or painful skin of the feet
There are different types of tinea pedis:
| Interdigital type (most common) | White or red, fissured, scaling skin or macerated areas in the interdigital areas
Most commonly affects the lateral interdigital space between the 4th and 5th toes and then spreads medially |
| Moccasin or dry-type | A more diffuse, chronic presentation causing scaling, erythema, and hyperkeratosis of the sole and lateral aspect of the foot
Dorsal foot surface is usually spared |
| Vesicobullous type | An inflammatory variant with hard, tense, small (1–5 mm) vesicles, blisters, bullae, and pustules on an erythematous base, mainly on the arches and soles of the feet |
Investigation and Diagnosis
Test of choice: skin samples for fungal microscopy and culture
Management
General Management / Self-Care Advice
Self-management:
- Foot hygiene
- Wear well-fitting, non-occlusive footwear that keeps the feet cool and dry
- Wear a different pair of shoes every 2-3 days
- Wear cotton, absorbent socks
- Dry the skin after washing the feet (esp. between the toes)
- Avoid scratching affected skin (as this may spread the infection to other sites)
Measures to prevent spread and transmission:
- Replace old footwear which could be contaminated with fungal spores
- Do not share towels, and wash frequently
- Wear protective footwear when using communal bathing places, locker rooms, gyms
If a child is affected, it is NOT necessary to exclude them from school or nursery
Antifungal Treatment
| Mild AND non-extensive disease | 1st line: topical antifungal cream
Consider a mildly potent topical corticosteroid (e.g. hydrocortisone 1%) if there is associated marked inflammation 2nd line options:
|
| Severe OR extensive disease | Consider oral antifungal
|
In children, 1st line is topical imidazole.
Topical terbinafine cream is NOT licensed in those <12 y/o
References