Anaphylaxis is a severe, potentially life-threatening allergic reaction affecting the whole body, often within minutes of exposure to the allergen (the substance to which the person is allergic). In some cases, anaphylaxis can happen few hours after the exposure to the allergen.
The body has an immune system that defends it against foreign substances (such as bacteria, virus, parasites, etc.). Sometimes the immune system is activated by certain substances which set off a series of chemical reactions in the body leading to allergic reactions. In most cases, allergic symptoms such as itching, sneezing, rashes are not life threatening. However, in some people, there can be severe allergic reactions leading to anaphylaxis.
Common triggers for anaphylaxis
- Food allergies: Food items such as peanut, nuts (walnut, cashew nuts, almonds), eggs, milk, fish, shellfish, certain fruits (bananas, kiwi fruit, grapes).
- Insect bite or stings: Any insect bite or stings could potentially cause anaphylaxis. The most common causes are stings from wasps or bee.
- Medications: Some medications can trigger anaphylaxis including antibiotics (especially penicillin group), painkillers (such as ibuprofen, aspirin), anaesthetic agents, muscle relaxants, etc.
- Contrast agents: Certain special dyes called contrast agents used during some X-rays and scans can cause anaphylaxis. For examples dye used during angiography.
- Rubber Latex: Natural rubber latex allergy is present in many individuals. Exposure to latex is one of the important causes of anaphylaxis.
Those who have pre-existing allergic conditions such as hayfever, asthma, eczema are more likely to be affected by anaphylaxis. Those working in healthcare, catering, automobile and beauty industry are at a higher risk.
The symptoms and signs of anaphylaxis can develop rapidly, and usually, the peak severity is reached within 3- 30 minutes. In some instances, the symptoms may occur for few hours or rarely for days.
The symptoms can include any of the following features:
- Raised skin, itching and red skin rash
- Swelling of eyes, redness of eyes, tearing
- Itching of the lips, tongue or the roof of the mouth
- Running nose, blocked nose, sneezing
- Breathing difficulty due to swelling of the tongue, pharynx or larynx, chest tightness, cough, wheezing
- Swelling of the mouth, throat or tongue, which can cause swallowing and breathing difficulties
- Swelling of hands and feet
- Nausea, vomiting, diarrhoea, abdominal pain, an urgency to defecate or leakage of faeces
- Urine urgency or leakage of urine
- Uterine cramps, urinary urgency or incontinence.
- Feeling of impending doom
- Weak, rapid pulse, lightheadedness, faintness, irregular heartbeat, chest pain, syncope (loss of consciousness)
Anaphylaxis can be life-threatening, and death can occur within minutes if immediate medical care is not received.
The doctor will be able to diagnose an anaphylaxis episode by the classic symptoms and signs. Your doctor may ask questions about consumption of any foods or drugs known to cause allergy, any insect bites or stings and exposure to latex.
After treatment, tests may be done to determine the allergen which caused the reaction. This test may include skin prick tests or blood tests. You may be asked to maintain a food diary to record the food items consumed to determine if you have any specific food allergies.
- Anaphylaxis is an emergency condition and calls for medical help (ambulance) right away. Reassure and calm the person.
- A bee sting initiated anaphylactic reaction will usually have the stinger in the skin, which should be removed using a firm object. Do not use any tweezers, as squeezing the stinger can release more venom.
- If you are a bystander, check the person’s airway, breathing and circulation (ABC of Basic Life support).
- To prevent the person going to shock, make the person lie flat, preferably with the legs raised. If the person is vomiting, lay them on their side. Do not place any pillow or support under the head.
- Some people who get repeated anaphylaxis attacks may carry allergic medications with them, help them take or inject those drugs. When the person is having breathing difficulty, avoid giving oral medications.
- When there is breathing difficulty, the person may want to sit, as this may ease the breathing. Be careful as this may trigger a drop in BP. If the person is in this position, closely monitor the patient and if there is any alteration in consciousness or person feels faintness, lay the patient flat again.
- If the person is having coarse sounds when breathing or a hoarse voice, it is a warning sign of dangerous swelling in throat or airway. If required, start giving the person rescue breathing. If there are no heartbeats, begin chest compressions.
When the ambulance arrives, use the stretcher to shift the patient to the ambulance. Even if they appear to have recovered do not make them walk to the ambulance.
When the ambulance arrives, the emergency medical team may perform cardiopulmonary resuscitation (CPR) if the person has stopped breathing or the heart has stopped beating. They may insert a tube through the nose or mouth into the airways (endotracheal intubation). In severe cases, they may create an opening in the trachea (tracheostomy) for securing the airways.
Some medications may be given including:
- Adrenaline (epinephrine) to counter the allergic reaction in the body
- Oxygen to replenish the reduced oxygen in blood due to blocked airways
- Injections of corticosteroids and anti-histamines to counter the allergic reaction and the inflammation in airways.
- Medications (such as beta-agonist albuterol) to relieve breathing symptoms.
- IV fluids (drip) to increase the fluids in circulation and counter the hypotension (fall in BP)
- Blood vessel constrictors and heart stimulants (such as dopamine) to counter the drop in blood pressure.
Detection of allergen
If you have anaphylaxis, you should undergo an evaluation to find the causative allergen and which medication can help prevent further episodes. Identifying the allergen will help you avoid future episodes of anaphylaxis. Such tests include:
Skin prick test: A small amount of the allergen is pricked on to the skin to see if it becomes red, raised and itchy.
Blood test: Blood tests such as total tryptase and histamine tests.
You may be prescribed an adrenaline auto-injector (to give yourself adrenaline injection) if you’ve had a previous episode of anaphylaxis and there is a risk of you having another episode in the future.
If the allergen that triggered your allergy is identified, avoid exposure to it. Check food labels for the constituents and tell restaurant staff about any foodstuff you are allergic to. Move away from insects and use insect repellants. Inform your doctor about any medicines that you are allergic to, before he writes the prescription.
Anaphylactic reaction when severe can be life-threatening and result in death.
Other complications can include kidney failure and brain damage due to shock (severe drop in blood pressure) and low oxygen levels.
If you had an anaphylactic reaction, visit an allergic clinic to help determine what is causing allergy and initiate treatment to prevent future attacks.
Learn how to give yourself adrenaline injections in case of an emergency.
Wear a medical alert bracelet or card that mentions about your allergy and what to do in the event of urgency. Inform your colleagues and friends about your allergy and injection you carry and how to administer it.
When you start having itching, skin rash, skin swelling, difficulty breathing, dizziness after any insect bite, food or drug intake consider the possibility of anaphylaxis, especially if you have allergic disorders (such as hay fever, asthma, eczema) and seek immediate medical attention or help from bystanders.
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- Medline Plus. Medical Encyclopedia –Anaphylaxis. Accessed at https://www.nlm.nih.gov/medlineplus/ency/article/000844.htm on 15 June 2016.
- Australasian Society of Clinical Immunology and Allergy (ASCIA). ASCIA Guidelines – Acute management of anaphylaxis. Accessed at http://www.allergy.org.au/health-professionals/papers/acute-management-of-anaphylaxis-guidelines on 16 June 2016.
- NHS Choices. Accessed at http://www.nhs.uk/conditions/Anaphylaxis/Pages/Introduction.aspx on 15 June 2016.
- American Academy of Allergy, Asthma & Immunology. Anaphylaxis. Accessed at http://www.aaaai.org/conditions-and-treatments/allergies/anaphylaxis on 16 June 2016.