What is anaphylaxis, anaphylactic reaction, symptoms and treatment

What is Anaphylaxis?

It is a severe allergic reaction that develops quickly, within one to two minutes, and it happens when the person is exposed to some allergen product to which their immune system has developed sensitivity. These allergens can be insect bites, food, medication and contrast agents that are used in x-rays.

Some of the symptoms that can appear are rash, low pulse, seizures , urinary incontinence, loss of consciousness, sudden brain attack and “anaphylactic shock”, which can be fatal if not treated quickly.

Once the body is exposed to substances it considers to be dangerous, it activates its immune system responsible for producing antibodies. However, some people overreact to these antibodies, which ends up causing anaphylaxis.


Anaphylaxis can be caused by several types of substances that, when they come into contact with the person’s body, even in small amounts, develops quickly. The most common reactions are caused by food, insects and medicines.


Children are more likely to develop a food allergy attack, which can be caused by:

  • Peanuts;
  • Fish;
  • Seafood;
  • Eggs;
  • Milk;
  • Soy;
  • Wheat.

As for adults, the most common foods are:

  • Seafood;
  • Walnuts, hazelnuts, cashews, pistachios and almonds;
  • Peanuts.

Some people are so sensitive to these foods that even the smell can trigger a reaction.

Insect bites

Any insect can cause a reaction, but most cases are caused by bees and wasps.


The drugs best known for causing anaphylaxis are:

  • Some remedies, such as Penicillin, Aspirin , Ibuprofen , Naproxen or Dipyrone ;
  • Anesthetic drugs that contain substances such as: suxamethonium , alkuronium, vecuronium , pancuronium and atracurium ;
  • Anti-inflammatory.

Most people sensitive to these drugs will usually develop anaphylaxis as soon as they start treatment with it.

X-Ray Contrast

It is a type of dye used for some tests, which will help to show a certain part of the body lighter. Although the risk for anaphylaxis is low, it is still possible.


It is a substance contained in medical equipment (gloves, for example), condoms and birthday balloons that, when in contact with the skin, can cause anaphylaxis.

Exercise-induced anaphylaxis

This type of anaphylactic attack is not common and varies from person to person. Some people may have a reaction when doing a strong aerobic activity, such as spinning, while others may have a seizure after a simple walk.

It is worth mentioning that it is not the exercise itself that causes the crisis. In reality, it is triggered after eating certain types of food, especially seafood, celery and wheat, and can happen after 2 minutes of exercise or up to half an hour later.

Other factors that can trigger the crises are the ingestion of drugs, climatic conditions such as too much heat and, for women, the proximity of the menstrual cycle.

Groups of risk

There are not many known risk groups for anaphylaxis, but some things can increase the chance of its development. Are they:

Allergies or asthma

Patients who are allergic to any substance or who have a respiratory problem such as asthma are at an increased risk of experiencing an anaphylaxis

A previous case of anaphylaxis

If you have had an anaphylaxis once, the risk of having another one increases, with the reactions getting stronger and stronger.

Family history

If you have family members who have had an exercise-induced anaphylaxis attack, the risk of developing this type of anaphylaxis is greater than for someone without a family history.

Symptoms of Anaphylaxis

First, the symptoms can be easily confused with the symptoms of a normal allergy , such as runny nose or some eczema . However, after about 30 minutes, more serious signs may appear. Are they:

  • Anxiety;
  • Abdominal pain;
  • Chest discomfort or tightness;
  • Swelling in the throat, lips and tongue;
  • Difficulty breathing, caused by the narrowing of the airways;
  • Diarrhea;
  • Difficulty swallowing;
  • Dizziness or vertigo;
  • Hives, itching and redness of the skin;
  • Nausea and vomiting;
  • Slurred speech;
  • Swelling in the face, eyes and tongue;
  • Unconsciousness.


The diagnosis can be made by any doctor who is in the emergency room, and based on the following symptoms:

  • Mental confusion;
  • Swelling in the throats;
  • Weakness and dizziness;
  • Fast or abnormal heart rate;
  • Facial edema;
  • Urticaria;
  • Low blood pressure (hypotension).

After the seizure is over, the doctor will ask about your allergies or any other allergic reactions you may have had by asking a few questions:

  • If any particular food or medicine seems to cause a reaction;
  • If you have been exposed to latex;
  • If insect bites seem to cause the symptoms.

To help with the diagnosis, the doctor may also ask you for some tests, such as the Prick Test and Patch Test, which are contact tests, where a specialist doctor will put you in contact with various substances that can cause a possible reaction, in addition to asking you to you keep a detailed list of all the foods you consume or, even, to give time for certain foods.

Anaphylaxis Treatment

If you are having a seizure or are close to someone who is having anaphylaxis, call an ambulance immediately.

The main treatment for an anaphylaxis reaction is adrenaline (epinephrine), which must be injected immediately after finding a crisis. It is important to check the expiration date of the medication, as the medication may be expired.

The usual dose for adults is 0.3-0.5 mg of a solution administered intramuscularly every 10-20 minutes or as needed. The dose for children is 0.01mg / kg up to a maximum of 0.3mg intramuscularly every 5-30 minutes if necessary. Smaller doses, such as 0.1 mg to 0.2 mg administered when necessary, are usually adequate to treat mild anaphylaxis, often associated with allergic skin testing or immunotherapy.

If the person who is having a crisis is unconscious, check that their airways are not obstructed so that they can breathe. Then, place it in a position that allows air to pass through your airways and also to ensure that it does not choke if you are going to vomit. It is also important to maintain sufficient ventilation and oxygenation in the brain above 91% that can be measured through your pulse.

If the person is conscious, but having difficulty breathing, he or she must sit down to facilitate breathing. If she is feeling weak, she should be lying flat and legs up to avoid a possible heart attack.

If the person having a crisis is a pregnant woman, she should lie on her left side to avoid putting too much pressure on one of the large veins that pumps blood to the heart.

If the person experiencing the crisis stops breathing, or the heart stops beating, cardiopulmonary resuscitation will be necessary.

Even if the injection was made with adrenaline, the person must be taken to a hospital to be observed, as the symptoms may return if the attack of anaphylaxis is not treated correctly.

Using auto injector

It is common for people who have had anaphylaxis to have their own Adrenaline injector. The device consists of a syringe with a hidden needle, which injects a single dose of the drug when pressed against the thigh.

It is important that you make sure you know how to use the auto injector. In addition, people close to you should also understand how the syringe works.

Medicines used in treatment

The most suitable drugs for the treatment of anaphylaxis are:

  • Decadron;
  • Epinephrine ;
  • Antihistamines and corticosteroids can also be used.


NEVER self-medicate or stop using a medication without first consulting a doctor. Only he will be able to tell which medication, dosage and duration of treatment is the most suitable for his specific case. The information contained on this site is only intended to inform, not in any way intended to replace the guidance of a specialist or serve as a recommendation for any type of treatment. Always follow the instructions on the package insert and, if symptoms persist, seek medical or pharmaceutical advice.


Without prompt and adequate treatment, anaphylaxis can end up resulting in:

  • Airway obstruction;
  • Cardiac arrest;
  • Respiratory arrest (where the person does not breathe);
  • Anaphylactic shock, causing death.

Living together

Having an anaphylaxis can be scary. So developing a step-by-step plan for those moments can help you, or the person experiencing a crisis, stay calm.

If you have a child who has anaphylaxis, it will be nice to share this plan with teachers, nannies and others who may be able to take care of the child as they will know what to do.


The best way to prevent anaphylaxis is to avoid the substances that you are allergic to.

The Healthy Minute brought some tips that can help you:

Leave some kind of alert in a place that people can see

There are some smartphones where it is possible to leave an alert message when it is blocked. Look for this setting on your cell phone and write down the substances you are allergic to. If your phone doesn’t have that option, you can still wear a bracelet or leave it written somewhere that people can see.

Always alert doctors about your drug allergy

When you go to the doctor and he prescribes a medication, ask about the substances it contains and talk about your allergies. However, if the doctor insists on proceeding with the medication, stay in the hospital for at least 30 minutes after taking the medication, so that you can receive the appropriate treatment in case you have a crisis.

If you are allergic to insect bites, be careful when they are close

If you are close to places that have insects, keep calm and walk away gently. Avoid slapping the insect.

If you know you are going to a place that may contain insects such as forests, try to wear long – sleeved blouses and pants. Also, do not walk barefoot on the grass, avoid colonies and sweet perfumes and use repellent.

If you are allergic to specific foods

Read the labels of all the foods you buy carefully. When eating out, always ask the waiter or chef what ingredients are used to prepare the dish.

Take anti-allergy to prevent crises

If you are allergic to x-ray contrasts , for example, and still need to use it for an exam, you can take injections of antihistamines and corticosteroids to prevent future attacks.

Keep an emergency kit with you at all times

Always keep your kit filled with medication within the validity period, including, even, an adrenaline auto-injector. See your doctor and ask for directions.

Anaphylaxis attacks are more common than we can imagine, but many people do not know how to react when they see a person having an anaphylactic attack. So, share this article with your friends so that this information reaches as many people as possible!