The most serious kind of allergic reaction is anaphylactic shock. It can kill by suffocation, the result of swelling of the larynx and obstruction of the airway. Anaphylactic shock can occur in response to insect stings, ingestion of allergenic foods in sensitive individuals, and injected or swallowed doses of medication. It is a medical emergency, but it can be treated effectively. Medical treatments for less serious allergic reactions are much less effective, and often toxic.
Antihistamines interfere with brain activity, causing drowsiness and depression.
Never use antihistamines if you have a tendency to depression or mental dullness. Even when these drugs do not depress mental activity, they merely suppress the allergy rather than cure it. As a result, the pattern of immune over-responsiveness is strengthened rather than weakened, meaning that more treatment will be required in the future. Never use cortisone, prednisone, or other steroid drugs to treat allergic reactions unless the allergies are very severe or life-threatening. Steroids perpetuate allergy through their suppressive action.