American Medical Association Family Medical Guide - American Medical Association [752]
Harmless petechiae called cherry angiomas can appear on the trunk, upper arms, and thighs after age 30. They may bleed if injured. Cherry angiomas may result from loss of skin elasticity with age.
Dilated blood vessels known as spider angiomas, or spider veins, are most common on the face (especially around the nose), breasts, arms, and legs. Spider angiomas often occur in girls during puberty, in pregnant women, and in women who are taking oral contraceptives or hormone therapy, possibly because hormones such as estrogen weaken vein walls. Spider veins can also occur in people with liver disease and after sun exposure or injury to the skin.
Other pigmentation changes
Some diseases (such as Addison’s disease; see page 899) and some medications (such as the acne medication isotretinoin or the antibiotic tetracycline) can cause the skin to darken. Other medications (such as birth-control pills) and some chemicals (such as perfumes) can intensify the effect of the sun on the skin and cause dark patches. Sometimes hormonal fluctuations during pregnancy or at menopause can cause changes in the skin, making patches of skin darker with sun exposure (a condition called chloasma). Cuts, abrasions, or acne sites that have healed can leave scars that stay discolored for a long time.
An excess amount of the bile pigment bilirubin can turn the skin yellow (jaundice; see pages 118 and 785), as can eating an excessive amount of foods that contain the orange pigment carotene (found in carrots, tomatoes, and some green vegetables). Too much iron can turn the skin bronze (hemochromatosis ; see page 961).
Boils
A boil (see page 122) is an infection of a hair follicle (a tiny pit in the skin from which a hair grows) by bacteria, usually staphylococcus. Boils are common and can result from poor hygiene or low resistance to infection. A carbuncle is the name for an unusually large boil or a group of boils that are joined together by small tunnels in the skin.
Bacteria from a boil may remain on the skin, possibly producing more boils. Bacteria from a boil can also contaminate food if a person does not wash his or her hands adequately before handling food (food poisoning; see page 783). In rare cases, the bacteria can travel through the bloodstream to other parts of the body, possibly causing a severe infection (blood poisoning; see page 937).
Symptoms
A boil starts as a red, warm, tender lump under the skin. Over a few days the lump becomes larger and more painful. As white blood cells (which fight infection), bacteria, and dead skin cells collect, the lump can develop a white or yellow head of pus. See your doctor if you have a large boil that doesn’t open within 2 weeks or if you have recurring boils.
Diagnosis
A doctor can diagnose a boil by its appearance and by a skin culture. If you have recurring boils, your doctor may take blood and urine samples to rule out the possibility that your boils are a symptom of diabetes (see page 889) or of a weakened immune system.
Treatment
To eliminate a boil as quickly as possible, apply a cloth soaked in hot water to the boil every few hours, or soak the boil in a solution of warm water and white vinegar. Wash the area with an antiseptic cleanser and apply an over-the-counter antibiotic.
Your doctor may open the head of a boil with a sterile needle or make a small cut in the center to allow pus to drain. He or she may prescribe an antibiotic. Your doctor may recommend treating recurring boils for several weeks with a combination of topical cleansers and antibiotics and oral antibiotics.
A boil usually bursts under pressure from the accumulated pus, relieving the pain. The boil heals after the pus drains. Boils may go away on their own, or burst and dissolve under the skin.
Warts
A wart (see page 121) is a lump caused by the human papillomavirus in the top layer of