Hives may be found on different parts of the body and do not stay at the same spot for more than a few hours. Contact dermatitis Contact with a plant substance such as poison ivy or oak, household detergents and cleansers, and chemicals in some cosmetics and perfumes. Itchy, red, raised patches that may blister if severe. Most of these patches are confined to the areas of direct contact with the allergen. The causes of allergies are not fully understood.
Children get allergies from coming into contact with allergens.
The tendency to have allergies is often passed on in families. A few children show signs of allergic reactions during infancy. Other children experience their first problems during adolescence. The first signs of eczema often occur in the first few years of life. Children with asthma and hay fever usually start to show signs during preschool or at least by early grade school.