Fungi of Skin - A Common Affliction

The human skin is a wonderful tissue which among its many functions also serves as an effective shield against invasion of our body by noxious organisms, including molds or fungi. However, the skin armor fails its protective function when it “rusts” or becomes damaged, as a result of combined humidity and heat, trauma to the skin or decreased immunity.

Many of the more than one hundred thousand species of fungi on our planet have adapted to live on human skin, and many do so in moderation without causing disease in the human host. It is only under conditions of the skin’s reduced resistance that fungi invade the human skin, and in certain instances even the inside of the body.

Fungal infections are the most common cause of skin disease, not only in the United States but also world wide. The most common fungal infections are caused by a group of fungi known as tinea or dermatophytes that tend to attack the scalp (the skin of the head), the skin of the body, the groins, and the feet. Other groups of fungi may also be involved in skin infections. The tinea or fungal infections are popularly named by a variety of names, some more appropriate than others, such as “athlete foot,” “jock itch,” and “ring worm” (although they are a fungal infection and not a worm invasion).

People who perspire freely or work in a hot or humid environment are more at risk of having a fungal infection of the skin.

The diagnosis is often made on the basis of the location and appearance of the lesions, but in more difficult cases, or in cases that do not respond to therapy, the fungal lesions may be scraped and cultured and examined microscopically and/or under fluorescent light.

The treatment consists of topical anti-fungal creams, as well as oral medications (e.g. Griseofulvin, Terbenafine, Ketoconazole, Itriconazole, Fluconazole, etc.).

Many of the topical antifungal creams are available as over the counter medications. However, the oral medications are available only by physician’s prescription because of their side effects. For example, griseofulvin, a common oral anti-fungal medication, may cause headaches, nausea, and rarely, temporary liver damage. Alcohol drinking is forbidden during oral anti-fungal therapy, because it may increase the liver damage and interferes with the effectiveness of the medication.

Ringworm of the scalp:

Tinea capitis or ringworm of the scalp is a fungal infection that affects primarily school age children, although in recent years it has been reported with increased frequency in adults. The infection may be transmitted through combs, brushes, barrettes, pomades, bed linen, stuffed toys and from person to person. Most children are not contagious if using topical and oral antifungal medication, and may attend school.

The fungus invades the hair shaft and causes the hairs to break and results in a fungal rash. The fungal rash consists of one or several reddish scaly patches usually associated with hair loss. Some lesions, if untreated, may become severely inflamed, boggy or ulcerated, a condition known as kerion. Such lesions may result in marked scarring and permanent patchy baldness. Occasionally, the fungi responsible for the scalp infection may produce atypical lesions presenting as black dot and blond dot ring worm, balding black dot ringworm areas, diffuse scaling, or as eczematous rashes, and the diagnosis may be much more difficult. Treatment requires application of topical anti-fungal creams, washing of the hair with Nizoral shampoo, as well as oral anti-fungal medication (Griseofulvin), usually for a period of eight weeks.

Ringworm of the face:

Tinea faciei or ringworm of the face is not a common site of fungal infection and often has an unusual presentation that mimics other skin conditions or rashes. This fungal infection may be contracted from dogs, cats, horses and cattle.

Tinea barbae or ringworm of the beard is a fungal infection of the bearded areas of the face and neck and occurs only in adult males. Oral griseofulvin is the best treatment. Patients with associated inflammatory reactions may require also oral cortisone like medication.

Ringworm of the body:

Tinea corporis or ringworm of the body is more frequent in children and youth living in a warm humid environment. The clinical symptoms are a result of the fungal byproducts that are toxic or cause an allergic reaction.

The lesions are usually slightly scaly, round or oval lesions with clear centers and well defined, slightly raised borders, and develop mainly in the outer layer of the skin (stratum corneum). The lesions are contagious and are spread mostly by infected household pets (especially cats or kittens) and occasionally through person to person contact.

The lesions usually respond well to topical antifungal creams. However, oral medication (Griseofulvin) may be required if the involved areas are extensive.

It is important to use the medications for one week after the lesions have cleared because there may be some residual infection within hair follicles. Household pets should also be treated to avoid recurrent infections.

Tinea versicolor:

Tinea versicolor is a mild, chronic fungal infection of the outside layer of the skin (stratum corneum) and is usually asymptomatic. Some patients do complain of itching, but this is usually mild and resolves as the rash is treated. The lesions have often a geographic like configuration with a somewhat branny appearance and appear as a discolored area of the body. On untanned skin the rash is pink to brown.

In tanned individuals, in which the fungus has prevented the tanning of the underlying skin in the affected areas, the lesions look white.

Tinea versicolor has a tendency to recur. Recommended treatments include application of Selenium sulfide 2.5% solution and antifungal creams. The uneven pigmentation can be treated with alpha hydroxyacid lotion.

Jock itch:

Tinea cruris or jock itch is a fungal infection of the groins, areas around the genitalia and the anus, and affects primarily adult men. It is not a contagious condition and direct person to person contact rarely causes an infection. Both groin areas are affected by moist reddish-purplish lesions with well defined, reddish, scaly and slightly elevated borders. The lesions are markedly itchy and may be occasionally painful.

The lesions usually respond well to topical antifungal creams applied twice daily to the skin. If the affected areas are very itchy or inflamed, a cortisone cream or ointment may be added. Recurrences may be prevented by wearing loose cotton underwear, dusting the groins with baby powder and drying thoroughly after bathing.

Athlete’s foot:

Tinea pedis or athlete’s foot is the most common fungal infection of skin. It is more common in adolescent males and in children whose father or older brothers have chronic untreated athlete’s foot. It usually begins as a white, wet, skin area that peels easily away between the toes. The lesions, more commonly seen in the webs between the fourth and little toes, spread progressively, are commonly associated with blisters, and are accompanied by itching or marked discomfort. The lesions may be complicated by a secondary bacterial infection.

People who have a tinea pedis infection and shave their legs may inoculate the fungus underneath the skin and may develop a deep skin infection of the roots of the hairs (hair follicles).

Usually antifungal cream with or without an antibiotic are sufficient, but extensive involvement may require oral griseofulvin.

To avoid recurrent infections it is recommended to keep the feet as dry as possible, use a foot powder daily, wearing socks which are at least 60% cotton and alternating two or three pairs of shoes, so they will always be completely dry. Open-toed sandals are recommended and boots should be avoided. It is also a good idea to wear slippers when showering in public places like gyms as these are prime places for this infection to be acquired.

Fungal infection of the nails:

Fungal infections of the nails (onchomycosis) are seen primarily in adults, and affect nearly 11 million Americans. The affected nails are usually thickened, discolored and show accumulation of debris under the nails and occasionally separation of the nail from the nail’s bed. Toenails are more frequently affected than fingernails.

The nail fungal infestations are difficult to treat and require both topical antifungal creams and oral griseofulvin for six months or more. Sometimes the fungal infections do not respond to the above treatments and other antifungal medications (such as oral itraconazole, terbenafine, etc.) may be required. These are also often treated with liquid antifungal solutions that are placed under the nail using a dropper.

Fungal ear infection:

Fungal ear infection (Otomycosis) is a superficial fungal infection of the outer ear canal. The infection is manifested by inflammation, itching, scaling and marked pain. Secondary bacterial infections are common. These infections are usually seen in persons with compromised immune systems.

Usually the patients are advised to clean the affected area with a Burrow’s solution, or a 5% aluminum acetate solution. In more severe cases a local antiseptic solution may also be prescribed.

Candida skin infections:

Candida albicans is a filamentous (thready) fungus which may infect not only the skin, but also the genital areas causing vulvar inflammation, the throat causing pharyngitis and even the inner viscera. Candida infections are seen in individuals with decreased immune capabilities such as diabetics, cancer patients and HIV positive patients. Oral antifungal medications such as Ketoconazole are commonly used in treatment.

In conclusion, fungal skin infections, although generally not life threatening, may cause marked discomfort and, if left untreated, may lead to significant chronic complications.