Fungal Infections of the Skin
Fungi (plural of fungus) are very simple, plantlike organisms at the bottom of the evolutionary scale. They grow in irregular masses and do not have roots, stems, leaves, or any pigments capable of photosynthesis. The fungi that infect human skin, hair and nails are specific types known as dermatophytes.
These superficial fungi invade only the uppermost layers of the skin. They do not penetrate into deeper tissues, other than occasionally involving hair follicles. Most people develop increased resistance after fungal infections, but about 20 percent are unable to do so and tend to have chronic, recurrent infections.
TINEA PEDIS (Athlete's Foot)
Fungal infections of the feet are quite common. Probably one half of young adult males are affected at some time. Women are infrequently affected, but athlete's foot is rare in children. (Rashes of the feet in children are almost always due to something else.) Damp feet clad in shoes are practically a prerequisite for the development of Tinea pedis. Shoes do not allow air to get to the feet and thus promote continuous dampness. Rough floors of locker rooms and pool decks may be prime sources, and the foot baths used in these places are of doubtful value. Tinea pedis is more of a problem in warmer weather and warmer climates.
The eruption of Tinea pedis is most often inconspicuous, but can be very bothersome. The usual symptom is itching. Three patterns are seen, sometimes more than one in an individual. The most frequent pattern is that of scaling, peeling, and cracking of the skin between the toes. There may be pain and tenderness if secondary bacterial infection of the cracks occurs. This type begins between the fourth and fifth toes and may spread to the spaces between the other toes. The space adjacent to the great toe is rarely involved. Another pattern often seen is the "moccasin-foot" distribution with fine, adherent scales over the soles and along the sides of the foot and lower heel. This type is very resistent to treatment. In the third type, fine blisters scattered over the soles are seen, especially in the instep. These may group together to form large blisters.
TINEA CRURIS (Ringworm of the Groin, or "Jock Itch")
Like Tinea pedis, "jock itch" is rare in children and uncommon in women. It is often associated with Tinea pedis and may be spread from the feet to the groin, giving rise to the tongue-incheek suggestion to put on the socks before putting on the shorts. Heat, moisture, and friction provide an ideal milieu for this fungus; thus it is often seen in heavy men and during the summer or in warmer climates. Athletic supporters or shorts which bind or chafe the skin aid the fungus. The prolonged wearing of wet bathing suits or athletic supporters is especially contributory. In women, tight-fitting slacks and panty hose provide a warm, damp environment for the fungus.
The rash begins at the junction of the scrotum and thighs and generally involves both sides. Characteristically, there are reddish-brown, scaly, half-moon patches on the inner thighs, in a "butterfly" pattern. The advancing edges are more active and inflamed and are clearly defined. These borders may be raised or bumpy. The center of the area may be scaly and darker, but is not as inflamed as the edge. The rash spreads down the thighs and may move around to the buttocks in chronic cases. The scrotum is not involved. Tinea cruris may be itchy or irritating, but often is not very bothersome.
TINEA CORPORIS (Ringworm of the Body)
This fungal infection occurs most often in children. In adults it may result from the slow, persistent spread of Tinea cruris to other parts of the body. Tinea corporis is more common in hot, humid climates but is not as dependent on the local factors of heat, moisture and irritation as Tinea pedis and cruris. Exposed skin is most often involved, and the rash may be sparse and localized. The patches are round or very irregular in outline and characteristically have a distinct, clear-cut, usually raised border. The border spreads outward while the center clears, in the same fashion as Tinea cruris.
TINEA MANUUM (Ringworm of the Hand)
Fungal infections of the hand are not common and are often incorrectly diagnosed. Eczema or dermatitis of the hands is far more frequent. Tinea manuum is almost always associated with Tinea pedis. For some reason, the fungus usually infects both feet but only on~ hand. The palm and palmar surfaces of the fingers are diffusely covered with fine, adherent, white scales.
ONYCHOMYCOSIS (Fungal Infection of the Nails)
Nail infections are seen more often in the toenails and are frequently associated with Tinea pedis. Nails are invaded at random and rarely will all be involved. The infection begins at the edge of the nail and moves up the nail towards the foot. The nail develops a yellow or whitish discoloration and becomes thick, brittle, and crumbly; it may partially separate from the naillbed. These changes may be slight or the entire nail may be considerably distorted and thickened. This pattern is very common in the elderly in whom it is often caused by yeasts or molds. This is significant if treatment is contemplated, because the medication that is most effective for dermatophyte infections of the nails (griseofulvin) is worthless against molds and yeasts.
TINEA VERSICOLOR
Tinea versicolor is a very common fungus infection that most often involves young adults. It is usually seen in those who are exposed to heat and humidity and appears in the spring and summer months. Tinea versicolor is most common in hot, humid climates, where it may affect a substantial percentage of the population.
The rash begins as small, flat, white or brown scaly patches on the back or chest. These patches may be very small and arranged around hair follicles. The rash may spread to the upper arms, neck, and lower trunk. Later, the patches coalesce to form large areas several inches in diameter. The involved skin often fails to tan, but may be darker than the normal skin, especially on untanned skin. Sometimes there is mild itching brought on by sweating; otherwise, there are no symptoms. This infection often lasts for years and frequently recurs after treatment.
These superficial fungi invade only the uppermost layers of the skin. They do not penetrate into deeper tissues, other than occasionally involving hair follicles. Most people develop increased resistance after fungal infections, but about 20 percent are unable to do so and tend to have chronic, recurrent infections.
TINEA PEDIS (Athlete's Foot)
Fungal infections of the feet are quite common. Probably one half of young adult males are affected at some time. Women are infrequently affected, but athlete's foot is rare in children. (Rashes of the feet in children are almost always due to something else.) Damp feet clad in shoes are practically a prerequisite for the development of Tinea pedis. Shoes do not allow air to get to the feet and thus promote continuous dampness. Rough floors of locker rooms and pool decks may be prime sources, and the foot baths used in these places are of doubtful value. Tinea pedis is more of a problem in warmer weather and warmer climates.
The eruption of Tinea pedis is most often inconspicuous, but can be very bothersome. The usual symptom is itching. Three patterns are seen, sometimes more than one in an individual. The most frequent pattern is that of scaling, peeling, and cracking of the skin between the toes. There may be pain and tenderness if secondary bacterial infection of the cracks occurs. This type begins between the fourth and fifth toes and may spread to the spaces between the other toes. The space adjacent to the great toe is rarely involved. Another pattern often seen is the "moccasin-foot" distribution with fine, adherent scales over the soles and along the sides of the foot and lower heel. This type is very resistent to treatment. In the third type, fine blisters scattered over the soles are seen, especially in the instep. These may group together to form large blisters.
TINEA CRURIS (Ringworm of the Groin, or "Jock Itch")
Like Tinea pedis, "jock itch" is rare in children and uncommon in women. It is often associated with Tinea pedis and may be spread from the feet to the groin, giving rise to the tongue-incheek suggestion to put on the socks before putting on the shorts. Heat, moisture, and friction provide an ideal milieu for this fungus; thus it is often seen in heavy men and during the summer or in warmer climates. Athletic supporters or shorts which bind or chafe the skin aid the fungus. The prolonged wearing of wet bathing suits or athletic supporters is especially contributory. In women, tight-fitting slacks and panty hose provide a warm, damp environment for the fungus.
The rash begins at the junction of the scrotum and thighs and generally involves both sides. Characteristically, there are reddish-brown, scaly, half-moon patches on the inner thighs, in a "butterfly" pattern. The advancing edges are more active and inflamed and are clearly defined. These borders may be raised or bumpy. The center of the area may be scaly and darker, but is not as inflamed as the edge. The rash spreads down the thighs and may move around to the buttocks in chronic cases. The scrotum is not involved. Tinea cruris may be itchy or irritating, but often is not very bothersome.
TINEA CORPORIS (Ringworm of the Body)
This fungal infection occurs most often in children. In adults it may result from the slow, persistent spread of Tinea cruris to other parts of the body. Tinea corporis is more common in hot, humid climates but is not as dependent on the local factors of heat, moisture and irritation as Tinea pedis and cruris. Exposed skin is most often involved, and the rash may be sparse and localized. The patches are round or very irregular in outline and characteristically have a distinct, clear-cut, usually raised border. The border spreads outward while the center clears, in the same fashion as Tinea cruris.
TINEA MANUUM (Ringworm of the Hand)
Fungal infections of the hand are not common and are often incorrectly diagnosed. Eczema or dermatitis of the hands is far more frequent. Tinea manuum is almost always associated with Tinea pedis. For some reason, the fungus usually infects both feet but only on~ hand. The palm and palmar surfaces of the fingers are diffusely covered with fine, adherent, white scales.
ONYCHOMYCOSIS (Fungal Infection of the Nails)
Nail infections are seen more often in the toenails and are frequently associated with Tinea pedis. Nails are invaded at random and rarely will all be involved. The infection begins at the edge of the nail and moves up the nail towards the foot. The nail develops a yellow or whitish discoloration and becomes thick, brittle, and crumbly; it may partially separate from the naillbed. These changes may be slight or the entire nail may be considerably distorted and thickened. This pattern is very common in the elderly in whom it is often caused by yeasts or molds. This is significant if treatment is contemplated, because the medication that is most effective for dermatophyte infections of the nails (griseofulvin) is worthless against molds and yeasts.
TINEA VERSICOLOR
Tinea versicolor is a very common fungus infection that most often involves young adults. It is usually seen in those who are exposed to heat and humidity and appears in the spring and summer months. Tinea versicolor is most common in hot, humid climates, where it may affect a substantial percentage of the population.
The rash begins as small, flat, white or brown scaly patches on the back or chest. These patches may be very small and arranged around hair follicles. The rash may spread to the upper arms, neck, and lower trunk. Later, the patches coalesce to form large areas several inches in diameter. The involved skin often fails to tan, but may be darker than the normal skin, especially on untanned skin. Sometimes there is mild itching brought on by sweating; otherwise, there are no symptoms. This infection often lasts for years and frequently recurs after treatment.
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