Anaphylaxis (allergic reaction) is an instant, potentially life-threatening systemic reaction that needs to be treated immediately to prevent undesirable sequelae. Anaphylaxis primarily affects the airway, breathing and circulation, and may go on to involve other systems of the body. Skin is also an organ that is often involved, presenting in the form of rash, swelling and itching. It is important to note, however, that some of the most severe forms of allergic reactions may not involve the skin at all.
The most widely reported triggers of anaphylaxis are:
- insect stings; particularly wasp and bee stings
- nuts; particualry peanuts
- other types of foodstuffs such as milk and shellfish
- certain medications such as some types of antibiotics
SIGNS AND SYMPTOMS
Anaphylaxis is a medical emergency the requires immediate recognition and intervention. Signs and symptoms of an allergic reaction develop rapidly and include the following:
Skin: flushing of the skin, redness, swelling and warmth. In addition to the skin, eyes may also appear excessively red
Respiratory: difficulty breathing is often the most common and most prominent sign of an allergic reaction, sneezing, runny nose, wheezing (whistle-sound while breathing in or out), shortness of breath, cough and hoarseness may also be seen.
Cardiac: dizziness, weakness, chest pain and palpitations
Neurological: headache, dizziness, blurred vision and very rarely seizures may be seen
Anaphylaxis is a clinical diagnosis, which means it is diagnosed on basis of clinical signs, and should be treated as a first priority as it can quickly threaten life. Patient’s airway should be assessed first and foremost, followed by breathing and circulation, level of alertness and orientation. Laboratory tests are not required or indicated in the first line management of an allergic reaction. They may be ordered after stabilizing the patient, for identifying underlying causative etiology.
An adrenaline injection must be given as soon as a serious reaction is suspected; often times patients with diagnosed allergies, especially to certain food carry anti-allergy medication in the form of pens with them. Adrenaline causes the blood vessels to constrict (become narrower), which raises your blood pressure and reduces swelling. It also causes the airways to open, relieving breathing difficulties, and suppresses the release of histamine. There are two types of auto-injectors:
- EpiPen. This needle releases adrenaline when it is jabbed against the outer thigh.
- Anapen. You hold the syringe against the outer thigh and push a button, which plunges the adrenalin-loaded needle into muscle.
Make sure you do not accidentally inject into a fatty part of their leg as the adrenaline cannot move through fat, or into a vein or artery as this can cause dangerous side effects. The injector should only be placed firmly into muscle.
After injecting, the syringe should be held in place for 10 seconds. The injections can be given through clothing.
Most people should experience a rapid improvement in symptoms once the adrenaline has been used. If there is no improvement after five minutes then you should inject a second dose of adrenaline, if one is available.
If the person is unconscious, check their airways are open and clear and check their breathing. Then put them in the recovery position (see below).
Putting someone who is unconscious in the recovery position (knees to chest, in left lateral position) ensures that they do not choke on their vomit.
Place the person on their side, ensuring that they are supported by one leg and one arm. Open the airway by tilting the head and lifting the chin.
If the person’s breathing or heart stops, cardiopulmonary resuscitation (CPR) should be performed.
Most patients will have instant recovery with Epi-pen. However, even after resolution of symptoms they should be brought to the hospital for further evaluation and treatment if necessary.