The doctor greeted her warmly. Then, more sternly, said: “It looks like you have a suntan. Have you been out in the sun?” It wasn’t the first time she heard that. “My friends keep saying that!” she exclaimed. She hadn’t been anywhere warm, didn’t go to tanning parlors, didn’t use tanning products. She didn’t know why her skin looked darker. And really, she felt so awful these days that she didn’t have the energy to even wonder about it.
Bock knew that some of his patients didn’t immediately acknowledge their tanning habits. But he could tell that wasn’t the case with this patient. He stepped out of the exam room and went to his office. At his computer, he searched for causes of hyperpigmentation. Two rare disorders came up immediately: hemochromatosis — an inherited disease in which patients are born without the chemicals needed to get rid of excess iron. Over time, these patients end up with too much iron in their system. When it collects in the pancreas, patients develop diabetes; in the joints, arthritis develops. And when it builds up in the skin, patients look darker.
The other disorder known to cause skin darkening is primary