Tinea Symptoms and Treatment
Fungi are members of the plant family, and a limited number of them can cause infections in humans. The vast majority of fungal infections occur on the skin, but other commonly affected areas include the vagina, mouth and gut. In rare cases, fungal infections can spread to the lungs, brain and other internal organs.
Tinea is a term that includes almost every fungal infection of the skin. Fungal infections prefer areas of the body where there is heat (under clothing, in shoes), friction (from tight clothes or skin folds rubbing together) and moisture (from sweat). Tinea is more common in the tropics than in temperate climates.
Ringworm is NOT caused by a worm, but is a fungal infection of the skin. The fungus settles in one spot on the skin, and after the infection starts, a red dot may be seen but is often missed because it is quite small. This dot slowly enlarges as the fungus spreads away from its central base. After a few days, the center of the red patch becomes pale again and similar to normal skin, because the infection is no longer active at this point. Meanwhile the infection continues to spread and forms an ever enlarging red ring on the skin. The same phenomenon can be seen in nature with mushroom rings that form on the ground after damp weather, because mushrooms are a giant, distant relation to the microscopic fungi that are responsible for ringworm.
The term tinea is often followed by a further Latin word which indicates the area of the body affected.
Tinea cruris (also called 'crotch rot') is the term for fungal infections of the groin. These are also more common in men than women, and have a peak incidence in the 20s and 30s. A red, scaly rash can spread out from the skin folds in the groin to cover the inside of the thighs, the lower abdomen and the buttocks. The rash is often itchy and feels constantly uncomfortable. It tends to recur in summer and with exercise.
Tinea pedis is the term for fungal infections of the foot (including athlete's foot). It is far more common in men than women, and uncommon in children. The most common site for the infection is in the skin folds under the toes, where it may cause cracking and pain. The clefts between the toes are another common site, but almost any part of the foot, including the sole, may become involved. On the sole of the foot, the fungal infection may appear as deep-seated blisters rather than a red rash. The infection is caught from infected skin fragments that may be found on damp floors (e.g. communal showers, swimming pool change rooms).
Tinea manum is a fungal infection of the hand. It is uncommon in children, and usually affects the palms and palm side of the fingers. It appears as a fine scale with a faint red edge. It is best treated by tablets rather than cream, because the thick skin of the palm makes it difficult for creams to penetrate.
Tinea corporis is the traditional ring-shaped ringworm seen on the chest, abdomen and back. It appears as a red ring on the skin, with a pale center. It affects both sexes and all ages equally. The infection may be caught by close contact with another infected human or animal (often cats, cattle and dogs). Without treatment, the ringworm may persist for many months, but it does not usually cause much itching or discomfort.
Tinea capitis is a fungal infection of the scalp that occurs almost exclusively in children. The infection appears as an irregular, relatively bald patch on the scalp, which is covered by broken hair stubble rather than the flexible long hair elsewhere on the head. The fungi invades the hairs and causes them to become fragile and break. The affected area of the scalp is also covered in a fine scale. A severely affected patch may develop a thick build-up of scale, and the disease is then called kerion. The infection is treated by a long course of tablets, and the result of this treatment is good.
Tinea unguium is the notoriously difficult-to-treat fungal infection that occurs under the nails. It is more common in the middle-aged and elderly. The nails appear white or yellow and gradually thicken. A very long course of tablets is the best treatment. Despite treatment, some of these infections persist for many years, particularly in toe nails, which are usually more severely affected than the fingers.
Doctors may occasionally refer to fungal infections by the name of the actual fungus that is causing the infection, rather than by the area that is affected. The common fungi affecting humans come from the Trichophyton, Microsporum and Epidermophyton families.
If a fungal infection is suspected, its presence can be proved by taking skin scrapings (obtained by scraping the edge of a knife or scalpel across the skin) and examining them under a microscope to find the spores of the fungi. Similar spores can also be identified on hair and nail clippings if these areas are affected. Ultraviolet light can also be used to diagnose some fungal infections, particularly of hairy areas. In an otherwise dark room, an ultraviolet light (referred to as a Wood's light medically) will cause a bright green fluorescence of hair and skin affected by a fungus.
Fungal skin infections can be treated with a wide range of antifungal creams, ointments, lotions, tinctures and shampoos. The choice of form will depend on the position and severity of the infection. There are now a number of antifungal tablets available, the most common being griseofulvin, but they are very slow to work, and must be taken for one to six months, again depending on the site of the infection.
Pityriasis versicolor (tinea versicolor) Pityriasis versicolor is a fungal skin disease of the tropics. It affects young adults more than the elderly and children. Initially, the fungus causes the development of pink/ brown patches on the body, which may have a very faint scale upon them. After the disease has been present for a few weeks, the skin underlying the infection has the pigment reduced, so that the rash appears as white patches. These patches are due to sunlight being unable to tan the skin underlying the patches of fungus, because the fungus produces a chemical (carboxylic acid) that prevents the formation of the brown pigment (melanin) that causes tanning. On the one patient, areas not exposed to sunlight (e.g. armpits, breasts) may retain the pink/brown patch appearance, while in sun-exposed areas (e.g. back, arms) the same infection can cause white patches to appear on the suntanned skin. This effect does not occur on Aborigines, Chinese and other dark-skinned races.
The chest, upper arms, neck, upper back and armpits are the most commonly affected areas. There are usually no other symptoms other than an occasional very mild itch, and patients see a doctor because of the adverse cosmetic effect caused by the rash. The diagnosis can be proved by examining skin scrapings under a microscope, but in most cases, the diagnosis is obvious to the doctor, and no investigations are needed.
Treatment involves the regular use of anti fungal lotions, rinses or creams. The white patches will remain for some time after the fungus has been destroyed, until the sun is given the chance to tan the area again. In years past, selenium sulphide (the active ingredient of the anti-dandruff shampoo Selsun) has been used to treat this condition, but more potent and effective anti fungals are now readily available. An antifungal tablet (Nizoral) is now used to kill chronic and widespread attacks of pityriasis versicolor.
Episodes of infection are quite easy to clear, but the infection recurs in the majority of victims, usually in the next summer. Some people appear to be susceptible to the infection, while others are resistant. The reason for this is unknown.
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