This condition is called Chronic Idiopathic Urticaria. In acute urticaria the condition usually occurs suddenly and resolves spontaneously within hours or days - the cause being obvious as will be discussed further. This is an uncommon condition and is experienced upon direct contact with a substance that causes a reaction. It differs from Allergic Contact Dermatitis in that a reaction occurs within minutes and is completely resolved within 24 hours. It is characterised by redness and swelling of the skin.
Treatment involves avoiding the offending substance.
Top Substances causing contact urticaria Medicines such as penicillin and salicylic acid. Foods such as dairy products, eggs, fruits, nuts, sea-foods and certain vegetables. Preservatives and additives such as benzoic acid, citric acid, sulphites, tartrazine and monosodium glutamate, however, that a detailed history of food or medicine consumption be noted to accurately identify the offending allergy. This condition is common, particularly in children. It is itchy with crops of papules appearing on the skin.