Tinea

Fungal infections of the skin and hair are often caused by dermatophytes such as Trichophyton or Microsporum. They can be spread between people (particularly children) or transmitted from animals or soil. In very rare cases they can become invasive in patients who are immunodeficient (Wang et al, 2020). However, even superficial skin infections can cause distress and social stigma.

When sending a specimen for identification by a mycology reference lab, it is critical to use good sampling technique and make sure plenty of material is collected. If you wish to carry out fungal microscopy yourself, you may wish to complete our free online course at Microfungi.net

Clinical lectures & videos

Ringworm

NAMES
Tinea corporis; ringworm; tinea gladiatorum (among wrestlers); tinea imbricata (AKA Tokelau)
Reviewed by Leung et al (2020), including tinea incognito and tinea imbricata.
DISEASE
LESIONS: Non-symmetrical patches, often circular or oval, with a slightly raised red edge and scaling. Usually not itchy. The appearances may be quite different after application of local steroid ointment or other topical agents. Infections acquired from animals can be inflamed and pustular.
SITE: Usually on exposed areas of the extremities, but may be on the body or neck.
FUNGI
Trichophyton rubrum; T. interdigitaleT. verrucosum; other Trichophyton spp. Microsporum canisM. audouinii; Epidermophyton floccosum
GLOBAL BURDEN
Worldwide and common, with a higher frequency in tropical and subtropical countries. Tinea imbricata is limited to Southeast Asia, India, southwest Polynesia, Melanesia, and Central America.
RISK FACTORS
Transmitted by direct contact with other infected individuals or animals. M. canis infections acquired from dogs and other furry animals. Severe infections may occur in immunocompromised individuals
DIAGNOSIS
Skin scraping with microscopy and fungal culture.
TREATMENT
Reviewed by Sahoo & Mahajan (2016)
Topical terbinafine cream over the lesions, oral terbinafine or itraconazole.
OUTLOOK
Excellent. Recurrence is likely if continued contact with infected humans or animals.

Tinea capitis

NAMES
Tinea capitis; kerion; favus
DISEASE
Tinea capitis appears as hair loss (alopecia) with little apparent inflammation. Well defined patches of hair loss start small and increase in size. In ‘black dot’ tinea capitis, hair breaks just above the scalp and diffuse swollen black dots appear. Clinical diagnosis requires the presence of broken hairs accompanied by scaling on the scalp, but can be difficult.
Kerion is an inflammatory mass of hair, exudate, fungus and granulation tissue that can mimic a squamous cell carcinoma, and is more common in children.
Favus is associated with red patches and scaling overlaid with disc or cup shaped yellow crusts (scutula) pierced by 1 or 2 hairs which do not break, with a distinctive, unpleasant odour.
FUNGI
Microsporum audouiniiM. canis;M. gypseum; several species of Trichophyton (T. interdigitale; verrucosum; T. tonsurans; T. soudanense; T. violaceum.
Favus is caused by T. schoenleinii.
GLOBAL BURDEN
Tinea capitis is worldwide in distribution, is more common in black adults and children with a global prevalence of 200 million cases. It is quite contagious and outbreaks may occur. In a recent US survey, tinea capitis was found in 6.6% children with ranges from 0% to 19.4%. It is more common in deprived areas. Favus is most common in remote areas of central and east Africa.
Read a systematic review of global data by Rodríguez‐Cerdeira et al (2020)
RISK FACTORS
Malnourished and deprived children are at greatest risk. Untreated infections may persist into adult life.
DIAGNOSIS
Microscopy of hair roots and culture
TREATMENT
Topical treatments are ineffective as they do not reach the inside of the infected hair shaft. The oral antifungals terbinafine, itraconazole and griseofulvin have similar efficacy, given for 2-6 weeks. M. canis infections are more difficult to treat and are refractory to terbinafine.
OUTLOOK
Recurrence can occur if infected family cats or dogs are not tested and treated if infected. Hair loss (alopecia) is usually reversible, but may be permanent if the infection is longstanding, or with kerion or favus.
MORE INFORMATION
Review on kerion by John et al (2016)
LIFE lecture (parts 1 & 2)

Tinea pedis

NAMES
Tinea pedis; athlete’s foot
DISEASE
The most common infection is between the toes, especially between the 4-5th toes and 3-4th toes. Cracking with a painful fissure is common.
Infection of the whole of the foot with a scaling eczema reaction and fissuring of the heel is also common (known as ‘moccasin type’). Occasionally an inflammatory reaction of the feet is seen.
FUNGI
Trichophyton rubrum; T. interdigitale; rarely others
GLOBAL BURDEN
Fungal infection of the skin, hair or nails affects ~25% of the world’s population (~1.5 billion)
RISK FACTORS
Athlete’s foot affects anyone at any age, but is more common in those who have dampness between their toes related to sports, swimming, frequent bathing or hot climates without drying between the toe webs.
Rates of up to 38% are seen among homeless persons (To et al, 2016).
DIAGNOSIS
Microscopy and fungal culture
TREATMENT
Terbinafine 1% cream or clotrimazole 1% cream. Oral itraconazole or terbinafine for moccasin type infection for 3 weeks
OUTLOOK
Responds well to therapy but tends to recur. Lower leg cellulitis complicates athlete’s foot.

Tinea cruris

NAMES
Tinea cruris; jock itch; genitocrural dermatophytosis
DISEASE
LESIONS: Confluent, red, scaly rash. A common differential diagnosis is cutaneous candidiasis, in which satellite lesions are common.
SITE: Generally covering the groin, scrotum and upper thighs. The central part of the rash may clear. The penile shaft is not affected. Intense pruritus (itching) is common. Localised scrotal infection is quite common and inconspicuous. There may be evidence of superficial fungal infection elsewhere on the body.
FUNGI
Dermatophytes such as Trichophyton rubrum and Epidermophyton floccosum, but Candida albicans can also affect damp areas where intertrigo is a problem
GLOBAL BURDEN
More common in men than women, and tends to occur between the ages of 18 and 60. Worldwide in distribution. Highly contagious; mini-outbreaks can occur e.g. in settings where towels are shared.
RISK FACTORS
None especially, other than sharing of bathing facilities.
DIAGNOSIS
Skin scraping with microscopy and fungal culture.
TREATMENT
Local application of topical antifungal cream twice daily for 2-3 weeks is usually sufficient. If there is evidence of extensive infection then oral therapy with itraconazole or terbinafine is better.
OUTLOOK
Excellent, although relapse occurs if other lesions on the body are not treated or treatment is not continued long enough.

Tinea manuum

NAMES
Tinea manuum
Read a more detailed guide at StatPearls or read a series of 18 Italian cases by Veraldi et al (2019)
DISEASE
Usually unilateral, especially on the right hand. Always asymmetrical. Two distinct forms. The dyshidrotic (eczematoid) form presents with raised scaly or vesicular lesions and marked itching and burning. The hyperkeratotic form gradually gets worse with a gradually enlarging dry area of involvement leading to extensive involvement of most of the palm and fingers. Fissures and thickening of the skin making the hands rough is common.
FUNGI
Trichophyton interdigitale;T. rubrum; Epidermophyton floccosum. Occasionally others.
GLOBAL BURDEN
Worldwide, frequency unknown but uncommon among skin fungal infections.
RISK FACTORS
None know; usually acquired from other infected individuals
DIAGNOSIS
Skin scraping for culture and microscopy.
TREATMENT
Topical azole therapy (econazole or clotrimazole) is usually successful, if applied for at least 10 days and possibly longer if extensive disease. Oral itraconazole (200 mg/d) or terbinafine (250 mg/d) are also highly effective, if given for 2-4 weeks.
OUTLOOK
Excellent outlook. Fingernail involvement should also be sought and treated.
Tinea manuum caused by T. rubrum

Pityriasis versicolor

NAMES
Tinea versicolor; pityriasis versicolor
DISEASE
Superficial skin infection of the upper trunk, usually without an inflammatory component or scaling. Depigmentation, like rain drops, or excess pigmentation over the chest or upper back is typical, especially after sun exposure.
FUNGI
Malassezia furfur (formerly Pityrosporum ovale) and other related species 
GLOBAL BURDEN
Common, especially in tropical and subtropical regions where up to 50% of the adult population may be affected. More obvious and perhaps more common in the summer months in temperate climates. Most common between ages of 20 and 40.
RISK FACTORS
Possibly genetic predisposition as family members not living together are more frequently affected.
DIAGNOSIS
Microscopy showing budding yeasts cells from the affected area.
TREATMENT
There are several topical treatments available containing sulphide selenium, propylene glycol and azole antifungals. Extensive cases sometimes require oral azole treatment with ketoconazole or itraconazole.
OUTLOOK
Rates of recurrence are very high. In some cases prophylactic itraconazole (200 mg one day per month for 6 months) has been used with a response of 88% at the end of the study.
Typical appearance of pityriasis versicolor
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