Skin is the largest organ on the human body, and an amazing number of things can go wrong with it. Here's a menagerie of skin diseases and conditions, all with full-color images that will have you checking yourself in the mirror for weeks. Some of the images are rather graphic. You've been warned.
1. Accessory nipples
Accessory nipples are just what they sound like—extra nipples that below the main nipples. They form in a line, as with the row of teats on a pig. Both boys and girls can get them.
In rhinophyma, your nose grows out of control, becoming bulbous and enflamed. It is a symptom of advanced acne rosacea, which causes chronic flushing of the face. Both Bill Clinton and W.C. Fields had rosacea, and caricatures of the men often show them having round, ruddy, red noses. Many folks with rhinophyma go on to have nose surgery.
3. Black Hairy Tongue
Black hairy tongue doesn't actually involve hair, nor is it necessarily black. Yeast or bacteria camp out on your tongue, where they produce the characteristic stain and make it appear to be fuzzy. Black is the most common, although many shades are possible, including brown, orange, and white.
An ancient disease, leprosy takes years to run its course. It can be 20 years before the first symptoms appear—a stuffy nose, cuts on the skin, and/or numbness—and longer still before the infamous flesh rotting sets in. Interestingly, scholars have been arguing for years (as seen in this 1909 New York Times article) that the leprosy mentioned so prominently in the Bible is not leprosy at all. If treated early, leprosy is highly curable. The World Health Organization has spearheaded a campaign to wipe out leprosy, with efforts now focusing on Brazil, India, Madagascar, Mozambique, and Nepal.
5. Hypertrichosis Lanuginosa
A diagnosis of hypertrichosis lanuginosa means you have hair growing all over your body—hair that is long, thick, and everywhere it should not be. The illness can be either inherited or acquired. The inherited form, known as Abras Syndrome, goes way back in history, according to medical historians. For instance, an extremely hirsute young man named Petrus Gonzalez from the Canary Islands was captured and "given" as a freak-show gift to the French nobility—who realized that there was nothing wrong with the guy except that he was completely covered in shaggy hair. They gave Gonzalez a castle, where he started family. Their portraits of Gonzalez show that many of his descendants inherited Abras Syndrome from him. The acquired form of hypertrichosis lanuginosa cause the fine hairs that your have on your face and elsewhere to thicken and lengthen. This condition is very rare. When it does occur, it's often as a result of cancer.
6. Cornu Cutaneum
Imagine looking into the mirror one morning—and seeing a horn sprouting from your head! That's the unfortunate predicament of folks with cornu cutaneum. These conical growths aren't actual horns, but rather tumors, sometimes benign and sometimes cancerous. But they look like horns, and that's the problem. One doctor described a patient with a horn three inches long (despite occasional trimmings) that had been developing for 30 years!
7. Human Papillomavirus
The human papillomavirus, often in the news for its association with cervical cancer, also causes numerous kinds of warts. In one extreme case, an Indonesian man with HPV developed pounds of thick, gray, bark-like warts. Since doctors hacked away the growths, the gentleman, Dede Koswara, has quit his job in a freak show and started searching for a wife.
[Most of these photos came from Johns Hopkins' online DermAtlas, which contains over 10,000 pictures of skin diseases.]