Many conditions, diseases, medicines, and lifestyle choices interfere with your ability to heal or fight infection. You may be at risk for a more serious problem from your symptoms if you have any of the following. Be sure to tell your health professional.

Conditions

• Age younger than 3 months
• Age older than 60
• Exposure to asbestos
• Living with smokers or being regularly exposed to secondhand smoke
• Previous surgery to remove the spleen (splenectomy)
• Recent hospitalization (may increase your risk for pneumonia)

Lifestyle choices

• Alcohol abuse or withdrawal
• Drug abuse or withdrawal
• Occupational exposure to smoke, dust, or fumes
• Smoking or other tobacco use

Medicines

• Angiotensin-converting enzyme (ACE) inhibitors such as captopril (Capoten), enalapril maleate (Vasotec), or lisinopril (Prinivil, Zestril, or Zestoretic)
• Corticosteroids, such as prednisone
• Medicines to prevent organ transplant rejection
• Medicines used to treat cancer (chemotherapy)
• Radiation therapy

Diseases

• Chronic upper respiratory illnesses such as chronic sinusitis, otitis media, or tonsillitis
• Chronic lung diseases such as asthma, chronic obstructive pulmonary disease (COPD, emphysema), bronchopulmonary dysplasia, cystic fibrosis, chronic bronchitis, tuberculosis (TB), or bronchiectasis
• Diabetes
• Gastroesophageal reflux disease (GERD)
• Heart disease, especially heart failure
• History of deep vein thrombosis, pulmonary embolism, or spontaneous pneumothorax
• Human immunodeficiency virus (HIV) infection
• Kidney disease
• Liver disease
• Stroke