American Medical Association Family Medical Guide - American Medical Association [627]
Treatment
Avoiding the problem food is the usual treatment for a food allergy. Carefully read the labels on all foods you buy. Ask about the ingredients in dishes you are served when you eat away from home, such as peanut oil used in many Asian dishes. Always carry the drug epinephrine (adrenaline) with you in a self-injecting device. Epinephrine dilates the airways and makes breathing easier. At the first sign of an adverse reaction to a food, immediately give yourself an injection and go directly to the nearest hospital emergency department.
Anaphylactic Shock
Anaphylactic shock (or anaphylaxis) is an extreme and sometimes fatal allergic reaction that requires immediate medical treatment. During an anaphylactic reaction, your body releases large amounts of histamine and other chemicals. These substances widen your blood vessels and cause a sudden drop in blood pressure. Your air passages narrow and may close completely, making it difficult or impossible to breathe. Anaphylactic shock may be triggered by any allergen, but most often occurs after an insect bite or sting, after eating a particular food, or after an injection of a medication.
If you are having a severe allergic reaction and you have never had one before, call 911 or your local emergency number. If you have had a severe allergic reaction before, always wear a medical identification tag around your neck or wrist that provides information about your condition. Also, your doctor will prescribe epinephrine (which improves breathing by widening the airways) in a self-injecting device. Carry the injection device with you at all times and give yourself an injection of epinephrine at the first sign of a severe allergic reaction.
If you are with a person who is having an anaphylactic reaction, call 911 immediately. If he or she becomes unconscious, lay him or her down with legs raised to improve circulation to the heart and brain.
Allergies to Medication
Some medications can trigger an allergic reaction. Drugs that are injected into a muscle or through a vein are most likely to cause allergic reactions because they enter the bloodstream directly. The medications that most often cause allergic reactions are penicillin and similar antibiotics. Oral medications are less likely to cause a reaction because some of the potential allergens are broken down during the digestion process. Many medications cause adverse reactions, or unwanted side effects, but because these reactions don’t involve the immune system, they are not considered to be allergic reactions.
Symptoms and Diagnosis
The symptoms of an allergic reaction to medication include rash, wheezing, or shortness of breath. If the symptoms are severe, they can lead to a life-threatening condition called anaphylactic shock (see left).
To diagnose an allergy to a medication, a doctor evaluates the person’s symptoms to make sure that they are not merely side effects of the medication. He or she will perform a blood test (RAST; see page 913) and skin tests (see page 912) to determine the cause and severity of the allergic reaction.
Treatment
Drug allergies can be treated in two ways. Avoiding the medication is the best treatment if the medication can be safely discontinued or if your doctor can substitute another drug. If you must have the drug that causes an allergic reaction and the reaction is relatively mild, your doctor may be able to treat the symptoms of the allergic reaction with another drug, such as an antihistamine or corticosteroid, to reduce inflammation. Be sure to tell any other doctors you see about your drug allergy so they won’t prescribe it for you. Wear a medical identification necklace or bracelet that specifies the type of medication to which you are allergic.
Autoimmune Disorders
When bacteria or viruses attack your body, your immune system defends you