Hives are a common cause of skin welts, according to the American Academy of Dermatology. Presenting as red or pink welts on the skin, hives are typically caused by an allergic reaction to food, medicine, animals, pollen and insect bites. Welts are also caused by bed bug bites, which typically appear on the skin in a zigzag pattern and are sometimes mistaken for hives, chickenpox or a rash.
Contact dermatitis, a skin rash that results from either long-term skin exposure to an irritant or an allergic reaction to an allergen, can also cause skin welts, explains the Cleveland Clinic. Topical medications, laundry detergent, preservatives, waxes and fragrances are examples of products that can trigger contact dermatitis.
Rosacea, which usually affects facial skin, can also cause welts, advises the Cleveland Clinic. Also called adult acne, the main signs of rosacea include persistent redness, visible blood vessels and frequent blushing.
Pityriasis alba is a common skin problem that results in the development of oval or round patches of skin, notes WebMD. The skin patches may initially look scaly and pink, but they eventually fade, returning the skin to its normal color. Anyone can get pityriasis alba, but it is most common in children. The skin patches appear more prominently on people with darker skin.