Anaphylaxis is a medical emergency that requires immediate treatment. Epinephrine is the most common drug used to reverse the symptoms of anaphylaxis. It constricts the blood vessels, prevents fluid leakage, opens the airways and raises blood pressure.  It also quickly relieves the itching and skin flushing that is part of most episodes of anaphylaxis. Epinephrine usually is injected in the thigh.

Physicians may direct patients with a history of severe reactions to carry their own epinephrine injection kit to treat themselves in an emergency. This epinephrine is delivered through a device known as an auto-injector. The epinephrine that comes with the auto-injector allergy kit usually is good for 18 months. The kit is only available by prescription.

A patient must be trained to properly use the syringe, as injecting epinephrine into the wrong place in the body can have dangerous consequences. Patients can practice by using a training device. It is also a good idea to make sure a patient’s family, friends and coworkers know how to administer the epinephrine in an emergency situation. Parents should alert the staff at their child's school about their child's risk for anaphylaxis and confirm that staff members know how to administer epinephrine.

Epinephrine should be taken at the first sign of anaphylaxis because a reaction that is treated quickly is less likely to become severe. An ambulance should then be called to provide additional medical treatment. When epinephrine is not available, medical attention should be immediately sought, either through calling an ambulance or driving the patient to a hospital.

Though epinephrine is highly effective in treating anaphylaxis symptoms, its effect can be diminished by beta blockers or angiotensin-converting enzyme (ACE) inhibitors (which prevent blood vessel constriction). These drugs are prescribed to treat high blood pressure and some heart conditions. Patients who use these drugs should make sure a physician knows of their use. The physician may recommend alternative medications for treating heart or blood pressure conditions for patients at risk of severe allergic reactions.

Additional treatment may follow the epinephrine dose. Physicians may instruct patients in advance to take an antihistamine following the injection, if the person is able to swallow without difficulty. These patients may benefit from keeping an antihistamine in their allergy kit. This drug does not stop the reaction, but it can reduce the severity of symptoms. 

Cardiopulmonary resuscitation (CPR) from a bystander may be required if a person becomes unconscious and stops breathing or does not have a pulse. Those who have suffered shock are likely to receive intravenous fluids and other medications to help support the actions of the circulatory system, including heart function. In rare cases, emergency personnel may perform a procedure to open an airway.

In about 10 percent of all cases, anaphylactic symptoms recur within four to 12 hours. This is known as a bi-phasic reaction. Antihistamines and corticosteroids may be prescribed to help reduce the chance of additional symptoms. Those who experience anaphylaxis should stay under medical supervision for a minimum of four to six hours after the attack subsides.