Many conditions, lifestyle choices, medications, and diseases 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 older than 60
• Cold temperature exposure (hypothermia)
• Dehydration
• Heatstroke
• History of irregular heartbeat
• History of transient ischemic attack (TIA) or stroke
• Personal or family history of a mental health problem, such as depression or schizophrenia
• Recent head injury
• Recent surgery of the head, brain, neck, heart, or blood vessels

Lifestyle choices

• Alcohol abuse or withdrawal
• Drug abuse or withdrawal
• Occupational exposure to toxins such as fumes, heavy metals, solvents, or pesticides

Medications

• Chemotherapy or radiation therapy
• Corticosteroids, such as prednisone
• Medications to prevent organ transplant rejection
• Recently started a new medication, changed the dosage of a medication, or have suddenly stopped taking a medication

Diseases

• Adrenal disease
• Alzheimer's disease
• Cancer
• Diabetes or low blood sugar (hypoglycemia)
• Heart disease, such as coronary artery disease, arrhythmia, or heart failure
• High blood pressure
• Human immunodeficiency virus (HIV) infection
• Hydrocephalus
• Kidney failure
• Liver failure
• Lung disease, such as severe chronic obstructive pulmonary disease (COPD) or emphysema
• Lupus
• Mental illness, such as schizophrenia or depression
• Multiple sclerosis
• Nutritional deficiency of vitamins B12, B1, or niacin
• Parkinson's disease
• Seizure disorder
• Stroke
• Thyroid disease, such as low thyroid (hypothyroidism) or high thyroid (hyperthyroidism)
• Transient ischemic attack (TIA)
• Wernicke-Korsakoff syndrome