The condition is usually caused by a genetic deficiency, but chemicals which affect metabolism may also cause it. Arsenic is an example. It can be triggered by various drugs or by some environmental conditions. The disease causes skin problems, or some diseases of the nervous system, or both. Severe pain is often present. Drugs are available that can at least treat the symptoms. This disease is most common in European countries and often affects the skin. When someone is affected by porphyria they will start to lose their hair about two weeks after having an attack. There is no cure for the hair loss. However, there is medication available to help prevent attacks.