This kind of skin inflammation with swollen
red itchy patches all over the body is the most common form of allergy
rash. The most common causes are certain foods like berries, shellfish, fish, nuts, eggs, milk, and others, medications, cosmetics, metals like nickel, emotional stress, exposure to water, sunlight, cold or heat, insect bites and
pollen.
Usually, skin rashes are not harmful and last only for few days.