Many conditions, medicines, and diseases interfere with the body's ability to heal or fight infection. Your child may be at risk for a more serious problem from the symptoms if he or she has any of the following. Be sure to tell your child's health professional.

Conditions

• Babies born prematurely. This risk continues until the child is 6 months older than when he or she was expected to be born.
• Babies younger than age 3 months
• Contact with infectious diseases, such as tuberculosis (TB)
• Exposure to tobacco smoke before birth (prenatal)
• Exposure to smoke, dust, or fumes
• History of any heart defects present from birth
• Living with smokers or regularly exposed to secondhand smoke

Medicines

• Corticosteroids, such as prednisone
• Medicines to prevent organ transplant rejection
• Medicines used to treat cancer (chemotherapy)
• Radiation therapy

Diseases

• Allergic diseases, such as atopic dermatitis (eczema) or hives
• Chronic respiratory diseases, such as cystic fibrosis and asthma, or a family history of these diseases
• Diabetes
• Diseases of the immune system, such as HIV infection
• Sickle cell disease