Contact dermatitis, eczema, and hives can be types of skin allergies.
Chemicals are the usual cause of contact dermatitis.
Two examples are poison ivy and self-care products. With poison ivy, the reaction to a plant chemical may not develop for 12 to 48 hours. A poison ivy reaction may cause redness and swelling, blisters, and severe itching. Chemicals in cosmetics or lotions may also cause skin problems. The symptoms may occur right away, or take a few days to develop.