The many causes of red blotches on skin include burns, infections, autoimmune diseases, allergies and hormonal changes, notes Healthline. It is important to speak with a professional regarding any lasting changes to your skin color.
Sunburns and other burns can cause skin damage, and some medications can make skin more likely to turn red when exposed to the sun, explains Healthline. Cuts and scrapes that develop infections can cause the surrounding skin to turn red. Infections caused by fungi, such as tinea versicolor and ringworm, can cause patches of skin to turn different colors. Autoimmune diseases such as lupus erythematosus and dermatomyositis can cause changes to skin color as well. Eczema is an allergy that causes red, scaly patches on the skin that ooze. Many rashes, such as dermatitis herpetiformis, contact dermatitis and poison ivy, can cause red, blotchy skin. Hormonal changes, especially ones that happen during pregnancy, can also cause changes in skin color.
Other reasons for red blotches on skin are port-wine stain birthmarks, according to Healthline. These are the result of swollen blood vessels and usually appear red or pink and flat. While skin cancer can change the color of your skin, radiation therapy also can cause burns that change the skin's appearance.