Athlete’s foot (known medically as tinea pedis) is a common fungal infection of the foot. It affects mainly adolescent and adult males. The tinea fungus read- ily grows in moist, damp areas such as shower stalls and ﬂoors. Sweating and inadequate ventilation of the feet provide ideal conditions for growth of the fungus.
The fungus can affect the skin between the toes or on the soles or sides of the feet. The affected skin itches, peels, cracks, and forms scales or blisters. Ath- lete’s foot also can affect the toenails, making them thicken, scale, and crumble. Fungal infections of the toenail can be very difﬁcult to treat. Untreated athlete’s foot can cause breaks in the skin, leading to a bacterial infection.
To diagnose athlete’s foot, your doctor will examine the affected areas of your skin and may remove a small sample of skin to examine under a microscope. The doctor will prescribe an antifungal cream to be applied to your skin. If the athlete’s foot is severe, he or she may prescribe oral antifungal medication. You will need to use all of the antifungal medication prescribed—even if your skin looks and feels better—to be sure that the infection has been completely elimi- nated.
To prevent athlete’s foot, keep your feet as clean and as dry as possible. Follow these useful tips to help prevent athlete’s foot:
• Dry your feet thoroughly, especially between your toes.
• Take your shoes off at home to expose your feet to the air.
• Wear sandals during the summer.
• Wear absorbent cotton socks and change them every day.
• Do not walk barefoot in locker rooms or at poolside. Wear thongs or reef shoes.
• Never share shoes.
• Shake an antifungal powder into your shoes in hot weather.
Boils and Carbuncles
A boil is a collection of pus beneath the top layer of skin. It is caused by bacter- ial infection of a hair follicle, the tiny pit in the surface of the skin in which a hair grows. Boils can cluster under the skin; such a cluster is known as a carbuncle. Boils may result from infection of a cut or scrape in the skin, poor hygiene, cos- metics that clog the pores, exposure to chemicals, and friction from tight cloth- ing or shoes. Perspiration contributes to the development of boils and carbuncles and can make them worse. Boils and carbuncles usually appear on the scalp, beard area of the face, arms, legs, underarms, and buttocks.
Boils begin as tender, inﬂamed, solid, sometimes painful bumps under the skin that enlarge as they ﬁll with pus. Sometimes the nearby lymph nodes also
become enlarged. Boils grow larger for a few days until they rupture, draining pus onto the surface of the skin. Carbuncles discharge their contents through a number of openings in the surface of the skin. Once they have ruptured, boils and carbuncles are less painful, but inﬂammation may persist for a few days or weeks. Scarring occurs in most cases.
You may be able to detect a boil on your own. Avoid squeezing or piercing a boil to open it up because the infection could spread. The best way to speed the opening of a boil is to apply warm, wet cloths to the area for 10 to 20 minutes several times a day. If you have a carbuncle or if the boil causes a fever or pain, see your doctor so he or she can prescribe oral antibiotics. In some cases, surgi- cal drainage may be required.
To prevent the spread of boils and carbuncles, do not let others use your tow- els or washcloths, and be sure to change your clothes and bed linens every day. Launder these items in hot, soapy water before using them again. And always wash your hands after touching the affected area.
Common Noncancerous Skin Growths
A variety of spots or growths can appear on the surface of your skin—especially as you get older—but most are harmless and do not require treatment. The most common noncancerous skin growths are actinic (or solar) keratoses, cherry angiomas, skin tags, age spots (also called sun spots or liver spots), moles, seborrheic keratoses, and warts.
An actinic keratosis is a skin growth that has a rough surface and can be red, skin-colored, or white. It is also called a solar keratosis because it is caused by excessive exposure to the sun over time. Actinic keratoses usually develop on fair-skinned people during middle age or old age. They most commonly appear on the face, hands, forearms, and upper chest. In a small percentage of cases an actinic keratosis can develop into a form of skin cancer known as squamous cell carcinoma (see page 428), so even though it is a noncancerous skin growth, your doctor may remove it. Actinic keratoses can be permanently removed with surgery, including laser treatment.
A cherry angioma is a bright red spot that may be raised or ﬂat and is composed of a collection of tiny, closely packed blood vessels near the surface of the skin. Cherry angiomas can develop on any part of the body but are most often found on the trunk. They increase in number after age 40. However, they do not become cancerous. Cherry angiomas that appear on the face can easily be removed for cosmetic reasons, but most are left untreated.
Small ﬂesh-colored or light brown ﬂaps of skin that protrude from the surface of the skin are called skin tags. They most often occur on the neck, upper chest, and underarms and around the eyes. Skin tags are harmless but can be irritating if they are persistently rubbed. Doctors can easily remove skin tags that are irri- tating or unsightly by cauterizing (burning) them with heat, chemicals, or elec- tric current, or by freezing them with liquid nitrogen.
Age spots (known medically as lentigines) are brown spots on the skin that resemble freckles and result from long-term exposure to sunlight. They are a sign that the skin is trying to protect itself from the sun by producing a pigment to help absorb the damaging sunlight. Age spots, also sometimes called sun spots or liver spots, appear in almost everyone as they get older, although they occur most frequently in fair-skinned people. Even people in their 20s or 30s can develop these spots—especially if they have fair complexions and have been exposed to excessive amounts of harmful sunlight. The spots most commonly occur on areas of the skin—such as the face, arms, hands, and tops of the shoul- ders—that are frequently exposed to the sun.
Treatment is usually not necessary unless you want to improve the appearance of your skin. You can purchase a nonprescription skin-bleaching cream at your local pharmacy to help fade the spots. There are a number of treatments available for age spots, including laser treatment to break up the pigment (color) in the spots, prescription skin creams, freezing with liquid nitrogen, or a chemical skin peel that uses a mild acid to remove the top layer of skin.
Moles are common skin growths that can appear on virtually any part of the body. Moles usually ﬁrst appear as brown or black spots that enlarge slowly over time, becoming elevated and lighter in color. Moles can become ﬂesh-colored, pink, tan, brown, or bluish black. Some eventually sprout hairs. Moles may darken with exposure to the sun.
Moles that are present from birth are known medically as congenital nevi. Moles that are larger than average or irregularly shaped or that have uneven color are called atypical or dysplastic moles. These types of moles have an increased likelihood of developing into the most serious form of skin cancer, malignant melanoma (see page 428). Any mole that changes, is asymmetrical, has an irreg- ular border, displays an uneven color, or is larger than a pencil eraser should be examined by a dermatologist.
Most moles are harmless and require no treatment. However, some men may want to have a mole removed because of where it is located or because it is unsightly. A doctor can remove a mole by shaving or cutting it away and then stitching the nearby skin closed. Repeatedly shaving a mole will not cause it to become cancerous, but you may want to have a mole in the beard area removed because it is constantly irritated. Moles are usually removed in the doctor’s ofﬁce.
As they age, many people develop seborrheic keratoses, which are tan, brown, or black; raised; crusted; or waxy spots that have a “pasted-on” look. They most often appear on the chest, back, scalp, face, and neck and can occur alone or in clusters. Seborrheic keratoses are harmless and do not develop into skin cancer, although black seborrheic keratoses may be difﬁcult to distinguish from skin cancer. A doctor can easily remove a seborrheic keratosis if it occurs in a loca- tion that affects your appearance. Doctors treat seborrheic keratoses by one of several methods: freezing them with liquid nitrogen, scraping them from the sur- face, burning them off using an electric current, or cutting them off with a scalpel or scissors.
Warts are skin growths caused by a viral infection. Warts usually are raised, rough, and ﬂesh-colored but can also be dark, ﬂat, and smooth. There are several different types of warts, including common warts, plantar (on the sole of the foot) warts, ﬂat warts, and genital warts (see page 184). Common warts typically grow on the hands and ﬁngers. They occur in areas where the skin has been broken, such as near bitten ﬁngernails or picked hangnails. Plantar warts can be painful when walking. Flat warts are small and grow in clusters of 20 or more. They can appear anywhere, but in adult men they usually occur in the beard area and are thought to result from skin irritation from shaving. Genital warts are a sexually transmitted disease that occur on the genitals and anus or inside the rectum. They have been linked to the development of cervical cancer in women and other genital cancers.
Warts are contagious, which means that the virus that causes them can be passed from person to person. A doctor usually can diagnose warts based on their appearance. Warts should be treated promptly to prevent spreading them to another person. In some cases, common warts may clear up on their own or may be dissolved with an over-the-counter medication. The preferred method of removal for common warts is freezing with liquid nitrogen. Plantar warts may need treatment with acid plasters, liquid nitrogen, or medicated creams. Flat warts are removed by using a chemical skin peel or medicated creams. Genital warts can be treated with imiquimod cream or podoﬁlox gel or may require freezing, acid treatments, or surgical removal.
Skin cancer is the most commonly occurring type of cancer in the United States. Experts estimate that 40 to 50 percent of Americans who live to age 65 will eventually develop some form of skin cancer. The risk is highest for people who have red or blond hair, light-colored eyes, and fair skin that freckles easily.
The two most common forms of skin cancer are basal cell carcinoma, which accounts for more than 90 percent of all skin cancers, and squamous cell carci- noma. Basal cell carcinoma is a slow-growing cancer, found in the base of the outer layer of skin, that rarely spreads to other parts of the body. Squamous cell carcinoma, which affects cells in the surface of the skin, also spreads infre- quently, although it does so much more often than basal cell carcinoma.
A less common type of skin cancer, malignant melanoma, is the most serious form of skin cancer. It spreads quickly and can be fatal. The number of people with melanoma has more than doubled in the United States since about 1980, giving melanoma the fastest-growing incidence rate of all cancers. Melanoma begins in skin cells known as melanocytes, which produce melanin, the pigment
Warning Signs of Malignant Melanoma
Melanoma is the most serious and dangerous form of skin cancer. It quickly spreads to other parts of the body and can be fatal. The incidence of melanoma is increas-ing faster than any other type of cancer in the United States. The ﬁrst sign of melanoma is often a change in the size, shape, color, or feel of an existing mole. Melanoma also can appear as a new black, blue-black, or red-bordered mole. Learn the warning signs of malignant melanoma so you can detect any changes in a mole early. Think of the letters “ABCD” to help you remember what to look for. (For pictures of suspicious moles, see page 92.)
• A—Asymmetry. Half of the mole does not match the other half.
• B—Border. The mole’s edges are often ragged, notched, blurred, or irregular in outline.
The pigment (color) may spread into the surrounding skin.
• C—Color. The color is typically uneven. Multiple colors—black, brown, tan, gray, red, pink, or blue—may be present.
• D—Diameter. The mole usually increases in size. Melanomas are typically larger than a pencil eraser (half an inch).
Melanomas vary greatly in appearance. Some have all of the above features; others may have only one or two. The most important thing to remember is to tell your doctor about any change you see in a mole as soon as possible so he or she can make a deﬁnite diagnosis. When detected and treated early, melanoma can be cured before it has a chance to grow and spread to other parts of the body.
that gives skin its color. When exposed to the sun, melanocytes produce more pigment, causing the skin to tan. Melanoma occurs when melanocytes become abnormal and begin to divide without control. The cancer cells then invade sur- rounding tissue and, in some cases, enter the bloodstream or lymph system to spread to other parts of the body. The ﬁrst sign of melanoma is often a change in an existing mole (see box on previous page). In men, melanoma often appears on the trunk, head, or neck.
The leading cause of all types of skin cancer is excessive exposure to ultravi- olet (UV) radiation from the sun, sunlamps, or tanning beds. The cumulative amount of exposure to UV radiation that you have had during your life deter- mines your risk of developing skin cancer—the more exposure, the greater your risk. Most skin cancers appear after age 40, but the sun’s damaging effects begin much earlier, in childhood. The most important thing you can do to reduce your risk of skin cancer is to limit the amount of time you spend in the midday sun.
The most common warning sign of skin cancer is a new growth or a sore that does not heal on your skin. The area may look like a small, pale lump or be ﬁrm and red. The lump may bleed or develop a crust. Skin cancer also can begin as a ﬂat, red spot that is rough, dry, and scaly. Skin cancer typically appears on parts of the skin—such as the face, neck, hands, and arms—that have been repeatedly exposed to the sun, although it can appear on any part of the body.
Early detection and treatment increase the chances for a cure. That is why it is important to examine your skin regularly for any changes. The best time to per- form a skin self-examination is after a shower or bath, using both a full-length mirror and a handheld mirror. Look for anything new—such as a change in a mole or a sore that will not heal. Check all areas of your body, including your face and neck, back, scalp, palms, forearms and upper arms, the backs and fronts of your legs, and your feet. Also check your genitals and the area between your buttocks. Use a comb to part your hair so you can examine your scalp. Examin- ing your skin regularly will help you to become familiar with the normal moles, birthmarks, and blemishes that are present on your skin so you can tell if there is a change in them. Your doctor will check your skin for any “suspicious” growths during a routine physical examination.
Treatment for skin cancer usually involves some form of surgery and, in rare cases, may also require radiation therapy or chemotherapy (treatment with pow- erful anticancer drugs). Many skin cancers can be cut out of the skin easily in a doctor’s ofﬁce. After numbing the affected area with a local anesthetic, the doc- tor scoops out the cancer with a spoon-shaped instrument called a curette and then controls bleeding and kills any remaining cancer cells by using an electric current. Most people are left with a ﬂat, white scar. Small skin cancers or pre- cancerous conditions such as actinic keratoses (see page 425) can be treated using cryosurgery, in which the area is frozen with liquid nitrogen and then peeled away. Doctors can use laser treatment on cancer that has affected only the
outer layer of skin. Laser treatment uses powerful, concentrated beams of light to destroy cancerous tissue.
When a large area of skin has been removed, the person who has been treated for skin cancer may need a skin graft to close the wound and ﬁll in the area of missing tissue. To perform a skin graft, the doctor will take some skin and tissue from another part of the person’s body and use it to replace the skin that was removed.
Doctors often use radiation therapy for cancers that appear in areas—such as the eyelid, ear, or tip of the nose—that are difﬁcult to treat with surgery. Radia- tion therapy is very effective for treating skin cancer, especially in older people, who are less likely to experience any long-term effects. Doctors may treat can- cers that are limited to the top layer of skin with creams that contain anticancer drugs such as ﬂuorouracil. Intense inﬂammation can follow such treatment.
Follow-up care is extremely important because skin cancer can recur in the same general location. About 40 percent of people who have had skin cancer will develop a second skin cancer within 5 years. If you have had skin cancer, examine your skin regularly for any changes, see your doctor for regular check- ups, and follow your doctor’s instructions about preventing a recurrence. Also remember to stay out of the sun as much as possible.
Dandruff (known medically as seborrheic dermatitis), the scaling and sloughing of the skin on the scalp, usually occurs during adolescence and adult life, reach- ing its peak severity at about age 20. In a person with dandruff, small white or gray scales accumulate on the surface of the scalp. The scales detach from the scalp, falling among the hairs and on the shoulders. Doctors once suspected that a yeast infection may have been the cause of most cases of dandruff, but current evidence shows that no microorganisms have a role in its development.
The best method of treating dandruff is shampooing with an antidandruff shampoo that contains selenium sulﬁde, zinc, or tar. After removal with a shampoo, however, the scales often form again in 4 to 7 days. If your dandruff is severe, see your doctor, who may prescribe an antidandruff shampoo. Daily shampooing will help prevent dandruff. Ask your doctor to recommend an over-the-counter hydrocortisone cream or ointment to help relieve itching and redness.
Our culture places great importance on hair and its appearance. Hair loss can cause embarrassment and loss of self-esteem. Your hair grows continually for
2 to 6 years, then rests for 2 or 3 months before falling out naturally. Shedding 50 to 100 hairs each day is a normal process, and each shed hair is replaced by
a new hair that begins to grow out of the same follicle. Your hair grows about a half inch every month, but, as you age, your rate of hair growth slows.
There are many different types of hair loss, with a number of different causes. A high fever or severe infection can produce hair loss, as can an overactive or underactive thyroid gland. Other causes of hair loss include an inadequate amount of protein in your diet, iron deﬁciency, or cancer treatment. Certain pre- scription medications—such as those for gout, arthritis, depression, heart dis- ease, or high blood pressure—can cause hair loss in some people. Large doses of vitamin A also can cause hair loss. If you notice that your hair is falling out in large amounts after you brush or comb your hair, see your doctor as soon as pos- sible to determine the cause.
For men, the most common type of hair loss is male pattern baldness, in which hair sheds from the top of the scalp and the hairline at the same time. Most men will experience some degree of hair loss as they get older. Thinning hair and baldness in men are usually inherited. Hair loss can be treated and controlled. Some men compensate for their hair loss by styling their hair differently or by wearing hairpieces, but there are now a number of effective methods for treating male pattern baldness.
A nonprescription medication called minoxidil is somewhat effective for regrowing lost hair. The drug does not produce results right away, but after about
4 to 6 months you may be able to see soft, downy hair in the bald areas of your scalp. The new hair may become the same color and thickness as your existing hair. Minoxidil is not effective for treating hair loss caused by anything other than hereditary male pattern baldness. If you stop using the drug, the hair loss will begin again.
Another drug, called ﬁnasteride, has been shown to be effective against male pattern baldness. Available only in pill form, the drug was originally used as a treatment for an enlarged prostate gland (see page 170). During such treatment, doctors noticed that some men regrew hair in balding areas of the scalp. The drug appears to increase the number of hairs in thin or balding areas while also slowing hair loss. You will need to take ﬁnasteride every day for at least 6 months before seeing any results. The predominant, although rare (for fewer than 2 per- cent of men who use the drug), side effect is impaired sexual function. Neither ﬁnasteride nor minoxidil is effective for replacing lost hair in a receding hair- line. As with minoxidil, if you stop using ﬁnasteride, you will continue to lose hair. (Warning: Women who could become pregnant must never use ﬁnasteride because the drug has been shown to cause birth defects.)
Hair replacement surgery (see page 442) can restore lost hair.