The infants considerable food requirements strain its as yet imperfect digestive system, giving rise to: gastrointestinal diseases (dyspepsia); gastrointestinal bacterial infections (dysentery, enterocolitis); chronic nutritional disturbances (infant dystrophy). Improper feeding and insufficient air and sunlight may lead to rickets. The vulnerability of the mucous membranes gives rise to pneumonias.
In early childhood incidence of acute infectious diseases increases: measles; whooping cough; chicken pox; scarlet fever; diphtheria. Susceptibility to tuberculosis is also greater. Allergies are more frequent and are a factor in the development of: bronchial asthma; rheumatism: eczema; nephritis.
Children of school age suffer endocrine disturbances, rheumatism, cardiovascular diseases, and psychoneuroses.