The main common causes of urticaria in infants and children are: congenital constitution, infections, dust mites, animal fur, pollen and diet (including food additives). Physical condition can be improved by medication and ageing; infection can be improved by effective antibiotics; food, dust mites, animal fur, pollen can be discovered by careful observation and keeping a diary of allergenic substances. Allergens can also be checked to discover common allergenic substances.