What Your Skin Says About Your Health Slideshow

Your skin can be a window to your underlying health, says Wake Forest University's Joseph Jorizzo, MD, one of the experts who literally wrote the book on skin signs of internal disease. Many underlying health conditions -- some very serious -- first appear as skin problems.

A butterfly rash across the face is often the first sign of lupus. But don't jump to conclusions. "It could be rosacea, it could be contact dermatitis. Unfortunately, sometimes it is a sign of lupus," says University of Miami dermatologist Paolo Romanelli, MD. Only further tests can tell if it's really lupus.

Velvety plaques in the neck and/or armpit suggest diabetes. This condition -- acanthosis nigricans -- could be benign or be caused by obesity. But it is very often a sign of diabetes. In rare cases acanthosis nigricans occurring in other places, such the hands or lips, may indicate an internal cancer.

Doctors call it necrobiosis lipoidica diabeticorum. As the name suggests, it's a distinctive sign of diabetes, but it is rare. It can first appear as a dull, reddish colored patch but then become shinier with a distinct border. Sometimes the affected skin may crack and become itchy or painful.

Lichen planus is a rash made up of reddish-purple, flat-topped bumps that may itch like crazy. It usually appears on the wrists or ankles, but may be in the mouth or on the lower back, neck, legs, and genitals. The cause isn't known, but if you have it, you may need to get liver tests. It could be linked to having hepatitis C.

Shagreen patches are flesh-colored lesions on the lower back that have the texture of an orange peel. They often occur with other skin signs: red or brown acne-like bumps spreading across the cheeks and nose; and ash-leaf spots of under-pigmented skin, most often on the trunk, that are oval at one end and pointy at the other. These are signs of a rare genetic disease called tuberous sclerosis that causes benign tumors to grow in the brain and other vital organs.

Tripe palms describes a skin condition in which the skin of the palm becomes thick and velvety-white with pronounced folds in the lines of the hand. The skin resembles boiled tripe. About 90% of cases can be linked to cancer. If only the palms are involved, it may likely be lung cancer. If tripe palms is accompanied by acanthosis nigricans, it's more likely stomach cancer.

First described in 1997, nephrogenic systemic fibrosis starts as a brown discoloration and indentation of the lower arms and legs. Very soon, the hands and feet become brown and like wood. Sometimes there's also a small yellow spot in the eye. Researchers have found that the dye used during MRI triggers this condition in some people with kidney disease.

Fortunately, necrolytic migratory erythema is pretty rare. It's a red, scaly rash, sometimes with small erosions of the skin, more often seen in elderly people. It tends to start in the fold of the buttocks or palms but can be elsewhere on the body. A bright red, painful tongue is common. The condition usually signals a pancreatic tumor, usually a glucogonoma.

Most skin problems do not indicate that anything else is wrong with you. For example, granuloma annulare is raised, reddish or flesh-colored bumps forming ring patterns that can be found on the hands and feet. They usually go away within two years and don't mean anything is wrong with you. If it is more widespread, then it may last longer.