Causes of ringworm

Ringworm or dermatophytosis is a fungal skin infection that may affect humans as well as animals.

About a 10-20% of the population will have some form of ringworm or fungal infection sometime in their lives.

Type of fungi that cause ringworm

Ringworm is caused by a particular type of fungi, called dermatophytes. These fungi live on keratin.

Keratin is the basic raw material that is tough and waterproof and is found in many parts of the body including the topmost layer of skin, nails and hair. (1-4)

Organisms that cause ringworm

Some of the organisms that may cause fungal skin infections like ring worm include (5) –

• Epidermophyton floccosum
• Microsporum audouinii
• Microsporum canis
• Microsporum canis var. disortum
• Microsporum cookie
• Microsporum equinum
• Microsporum ferrugineum
• Microsporum fulvum
• Microsporum gallinae
• Microsporum gypseum
• Microsporum nanum
• Microsporum persicolor
• Microsporum sp
• Trichophyton concentricum
• Trichophyton equinum
• Trichophyton mentagrophyes var. nodulare
• Trichophyton mentagrophytes var. erinacei
• Trichophyton mentagrophytes var. interdigitale
• Trichophyton mentagrophytes var. mentagrophytes
• Trichophyton mentagrophytes var. quinckeanum
• Trichophyton rubrum
• Trichophyton rubrum downy strain
• Trichophyton rubrum granular strain
• Trichophyton schoenleinii
• Trichophyton soudanense
• Trichophyton sp.
• Trichophyton tonsurans
• Trichophyton verrucosum
• Trichophyton violaceum

Types of ringworm infection

Types of ringworm infections include –

• Athlete’s foot – affecting the skin between the toes
• Diaper rash affecting diaper area of babies
• Groin infection or Jock’s itch
• Scalp infection called tinea capitis
• Nail infection called onychomycosis
• Infection of the whole body called tinea corporis
• Infection of hands called tinea mannus
• Infection of beard area and face called tinea barbae or faciei

How is ringworm spread?

Ringworm infection is spread by contact with the infected person or animals.

The spores of the lesion spread from person to person by direct contact with the infected lesion or by touching objects used by the infected person like bedding, clothes, towels etc.

The spores are tough enough to survive for months on the infected skin, in soil or on household objects, such as towels, bedding, socks, shoes and combs.

Ringworm can also be acquired from animals and pets like dogs, cats, cattle, sheep, pigs, rodents, rabbits and birds.

Touching farm equipment with spores on them can also transmit infection. The fungi also reside in soil. They may infect a susceptible person when they come in contact. (2)

Those at risk of getting the infection are infants and children, elderly, those with diabetes, obesity and depressed immunity like those with HIV AIDS or with cancer.

Those who are on chemotherapy drugs or on long term steroids are also vulnerable to dermatophytosis like ringworms. (3)

Further Reading

What is ringworm? 
Ringworm Symptoms
Ringworm Diagnosis
Ringworm Treatments