Skin allergies come in a few different forms. Also called allergic contact dermatitis, skin allergies appear when you touch something that you're allergic to. Other times, allergies to certain foods or airborne allergens may cause an allergic reaction in your skin. Reactions typically appear within a day or two of exposure to an allergen. Symptoms can be itchy, bumpy, red, blistered, swollen or painful skin.
Hives are a relatively common symptom of allergies that appear on your skin. Also called urticaria, hives are raised, red, itchy areas of skin and they can show up anywhere on your body. Hives are frequently related to food and drug allergies. Angioedema is another skin-based symptom related to food and drug allergies; it's when deep layers of skin become swollen and it isn't usually characterized by redness or itchiness. Angioedema commonly affects eyelids, lips, tongue, hands and feet.
Contact dermatitis is a symptom of an allergic reaction to something you've touched; it shows up in the form of a rash. It's normally not as itchy as it is painful. Meanwhile, allergic contact dermatitis typically is itchy, red and blistered; an example of allergic contact dermatitis is the reaction you get to poison ivy or poison sumac. Sometimes, allergic contact dermatitis involves a secondary bacterial infection, as well. People with dark skin occasionally end up with extra or too little pigmentation in the spot where they had an allergic contact dermatitis reaction.
Atopic dermatitis is a type of allergic reaction that's displayed on your skin. Also known as eczema, atopic dermatitis is a red, scaly and itchy rash that normally affects the face, elbows and knees. It can be caused by airborne allergens like dander and dust, or by contact with certain irritants. Other causes include food allergens, overheating and stress.