WD (Wrong Diagnosis.com) lists 2,331 medical conditions that can cause skin discolorations, and their list of types of skin discoloration is almost as long. Some medical conditions are simple and non-life threatening, while others are very serious. The American Academy of Dermatology recommends consulting a dermatologist if skin discoloration suddenly appears. A particular skin discoloration can stem from different causes.
Red is one of the most common colors for the skin to change to. WD reports 534 medical causes that can cause sudden reddening of the skin, including acne inflammation, an oncoming rash, burn, sunburn, dermatitis, fever, viruses and a reaction to certain medications. It, of course, can also be caused by flushing, which is the medical term for blushing. It can be caused by injury to the skin after bumping it against something hard. It may also result from coming in contact with something irritating, causing an allergic reaction such as a rash, the most common cause of redness.
Cyanosis is a medical condition that can be localized or affect the whole body, making lips and skin turn blue. Its cause is a lack of oxygen in the blood supply requiring immediate medical attention. Other causes of sudden blue discoloration are choking, drug overdose, shock, asthma, heart failure and cold exposure. Lung diseases such as pneumonia or pulmonary embolism may also cause the skin to turn blue.
The sudden onset of dark skin comes in various forms and colors including hyperpigmentation, purple skin, bronze skin, café-au-lait spots, black patches and more. Skin darkening might be a simple bruise or it might be the signal of some serious ailments, indicating medical attention is required. Hyperpigmentation is the result of specific skin cells releasing more pigment and can be caused by sunburn, adrenal disorder, Addison's disease, liver disorder or vitamin deficiency. It could be the appearance of a freckle, or it could be as serious as malignant melanoma or skin cancer.
Paleness or Whiteness
Vitiligo, hypopigmentation, leprosy, morphea and other conditions may cause white patches or spots. Sudden paleness can indicate fever, shock, anemia or leukemia. Hypopigmentation is the most common cause, and is the sudden lack of pigmentation in the skin. Hypopigmentation may result from skin damage, burns, infection, among other reasons.
Yellow and Orange
Jaundice is the most common cause of the skin turning yellow. Liver problems, such as alcoholic liver disease or cirrhosis make up the second most common reason. Hypothyroidism, HIV, syphilis and other diseases can also trigger a sudden yellowing of the skin. Carotenemia causes the skin to turn orange. If your skin turns yellow or orange, you should seek immediate medical attention.