Many conditions, lifestyle choices, medicines, 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 doctor.

Conditions

• Age older than 60
• A history of a brain tumor
• A history of physical or sexual abuse
• A personal or family history of depression or anxiety attacks
• Pregnancy
• Previous brain surgery
• Previous surgery to remove the spleen
• Travel to an altitude higher than 5000 ft (1500 m)
• Family or personal history of a brain aneurysm

Lifestyle choices

• Alcohol abuse or withdrawal
• Excessive caffeine use or caffeine withdrawal
• Drug abuse or withdrawal
• Smoking or other tobacco use

Medicines

• Birth control pills (oral contraceptive)
• Blood-thinning medicines, such as warfarin, heparin, or aspirin
• Cardiac medicines, such as nitroglycerin
• Corticosteroids, such as prednisone
• Hormone therapy, such as estrogen or progestin
• Medicines to prevent organ transplant rejection
• Medicines used to treat cancer (chemotherapy)
• Radiation therapy

Diseases

• Anemia
• Arthritis
• Brain tumor
• Cancer
• Diabetes
• Fibromyalgia
• Glaucoma
• Heart disease
• High blood pressure
• High cholesterol
• Human immunodeficiency virus (HIV) infection
• Hyperparathyroidism
• Hyperthyroidism
• Hypothyroidism
• Kidney disease
• Liver disease
• Lupus
• Lyme disease
• Mental health problems, such as anxiety disorders or depression
• Seizure disorder
• Sinus disease
• Sleep apnea
• Stroke
• Giant cell arteritis
• Transient ischemic attack (TIA)