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 health professional.

Conditions

• Age older than 60
• Anxiety
• Depression
• History of repeated concussions or head injuries, such as with football or boxing
• Pregnancy
• Previous brain surgery
• Previous serious head injury that required hospital admission or caused unconsciousness for longer than 5 minutes
• Problem that has been present since birth (congenital problem)

Lifestyle choices

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

Medicines

• Blood-thinning medications, such as warfarin (Coumadin), enoxaparin (Lovenox), heparin, and aspirin
• Corticosteroids, such as prednisone
• Medications to prevent organ transplant rejection
• Medications used to treat cancer (chemotherapy)
• Radiation therapy

Diseases

• Alzheimer's disease
• Amyotrophic lateral sclerosis (ALS)
• Anemia
• Brain tumor
• Cancer
• Diabetes
• Guillain-Barré syndrome
• Heart disease
• Hemophilia
• High blood pressure
• High cholesterol
• Human immunodeficiency virus (HIV) infection
• Huntington's disease
• Idiopathic thrombocytopenic purpura (ITP)
• Kidney disease
• Liver disease
• Lupus
• Ménière's disease or other diseases of the ear
• Multiple sclerosis
• Parkinson's disease
• Peripheral neuropathy
• Seizure disorder
• Stroke or transient ischemia attack (TIA)
• Thyroid disease
• Vascular disease