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
• Children and small adults
• Malnutrition
• Obesity
• Pregnancy
• Previous allergic reaction to snakes or lizards or to antivenom used to treat a prior bite
• Previous snake or lizard bite that required medical treatment
• Previous treatment with snake antivenom
• Previous surgery to injured area
• Previous surgery to remove the spleen
• Uncertain tetanus immunization history

Lifestyle choices

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

Medicines

• Anticoagulants, such as aspirin, heparin, or warfarin (Coumadin)
• Corticosteroids, such as prednisone
• Heart medicines, such as beta-blockers
• Medicines to prevent organ transplant rejection
• Medicines used to treat cancer (chemotherapy)
• Radiation therapy

Diseases

• Anemia
• Bleeding disorders, such as hemophilia or von Willebrand's disease
• Cancer
• Diabetes
• Eating disorders, such as anorexia nervosa or bulimia
• Heart disease
• Human immunodeficiency virus (HIV) infection
• Idiopathic thrombocytopenic purpura (ITP)
• Kidney disease
• Liver disease
• Neurologic diseases, such as multiple sclerosis, myasthenia gravis, or Parkinson's disease
• Peripheral arterial disease
• Sickle cell disease