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 mental health disorder or a history of mental illness
• Mental retardation with the inability to control muscles
• Previous brain surgery
• A previous head injury or concussion

Lifestyle choices

• Alcohol abuse or withdrawal
• Drug abuse or withdrawal
• Having guns in the home
• Not taking routine safety precautions, such as use of seat belts or head protection when playing contact sports, motion sports (such as skiing, snowboarding, rafting, kayaking), or while using open vehicles (such as bicycles, motorcycles, ATVs)
• Participating in high-risk activities, such as football, soccer, boxing, and sky diving

Medicines

• Aspirin
• Anticoagulants, such as warfarin (Coumadin) or heparin
• Corticosteroids, such as prednisone
• Medicines to prevent organ transplant rejection
• Medicines used to treat cancer (chemotherapy)
• Nonsteroidal anti-inflammatory drugs (NSAIDs), such as Advil or Motrin

Diseases

• Cancer, especially a brain tumor
• Hemophilia
• Idiopathic thrombocytopenic purpura (ITP)
• Liver disease
• Seizure disorder, such as epilepsy
• Neuromuscular diseases, such as cerebral palsy or Parkinson's