Jock Itch and other dermatophytes...
"Is Jock Itch caused by a fungus?"
Some fungi can grow on your skin, causing several different conditions including jock itch, athlete's foot and ringworm. These fungi are known as dermatophytes.. There are about 40 species in three genera.
Cutaneous
Infections
These fungi are not really parasitic in the sense of attacking
living tissue. They attack the dead cells of the epidermis,
and cause a kind of dermatitis. The irritation caused by
the fungus stimulates the skin cells to divide more rapidly.
This means that more flakes of skin containing infective
mycelium will be shed.
20 of the dermatophytes grow only on people, causing diseases called ‘tineas' . These occur on various parts of the body. They may affect the scalp ‘tinea capitis' (ringworm of the scalp), the groin ‘tinea cruris' (jock itch) and the feet ‘tinea pedis' (athelete's foot).
‘Tinea capitis' is often caused by Microsporum audouinii or Trichophyton tonsurans. Ringworm of the scalp is recognized as round, spreading patches of irritation and/or baldness.
‘Tinea cruris' - ‘Crotch Rot' and ‘tine pedis' athlete's foot is caused by Epidermophyton floccosum.This produces short-lived infections and relies on shed skin for quick spread to other hosts.
Usually these fungi are contracted in change rooms from small pieces of shed skin, but spores can survive in carpets and upholstery for up to 2 years.
Microsporum canis has its reservoir in the cat. It can cause ringworm of the scalp or body. It can be transmitted to dogs or people but will die out after one or two person to person transfers.
Trichophyton rubrum causes chronic infections of the foot and toenails and can produce infective material for several years.
Treatment
Topical treatments for athlete's foot and ringworm are Tolnaftate
(Tinactine) Canesten (Clotrimazole), haloprogin, miconazole
nitrate. More persistent cases can be treated by oral doses
of Griseofulvin, an antifungal antibiotic derived from Penicillium
griseofulvum.
A much more detailed account can be found in The Fifth Kingdom