"At the moment we have a new way of immunotherapy, especially useful for children, which consists of applying drops under the tongue. This avoids punctures and can be applied at home".


What is anaphylactic shock?

Anaphylactic shock, also known as anaphylaxis, is an extremely severe allergic reaction that affects the whole organism and occurs within minutes of exposure to the allergen. It could also be defined as an "explosive" reaction of the immune system to an external agent that triggers the release of chemical mediators by the immune system, such as histamine, causing a series of symptoms and clinical manifestations.

It is characterized by an immediate, systemic response of the body to exposure to a substance to which the individual is allergic. This extreme allergic response can be triggered by foods, medications, insect bites, latex and other physical factors such as cold or intense exercise.

Despite the high incidence of allergic diseases, this condition is very rare, its incidence is estimated at 1% of the population.

What are the symptoms of anaphylaxis?

It affects several organs at once: the most frequently involved are the skin, the cardiovascular, respiratory and sometimes the digestive system. Symptoms develop rapidly.

The clinical picture usually begins with intense itching in palms and soles, scalp and genital area. It usually continues with intense palpitations (tachycardia), which may be accompanied by generalized intense redness, breathing difficulty, diarrhea, dizziness and loss of consciousness. If left untreated, it often leads to cardiocirculatory collapse.

What are the most common symptoms?

  • Itching
  • Tachycardia
  • Widespread intense redness
  • Breathing difficulty 

Do you have any of these symptoms?

You may have suffered anaphylactic shock

What are the causes of anaphylactic shock?

The most common causes of anaphylaxis are ingestion of allergenic foods, administration of medications to which the individual is allergic, poisonous insect bites, contact with latex, and exposure to physical triggers.

These factors can vary widely from person to person, and it is important to identify the exact cause to prevent future reactions.

Requires immediate medical attention.

What precautions should be taken?

Once the allergens have been identified, measures should be taken to avoid contact or exposure.

  • Avoiding exposure to the allergen that has caused the reaction is key to preventing it from happening again.
  • In the case of foods, collect information about those containing that substance and eliminate them absolutely from the intake.
  • In the case of wasp or bee sting allergy, there is a vaccine that is highly effective.

How is anaphylaxis diagnosed?

Anaphylactic shock is diagnosed by the clinical picture the patient presents. These are very characteristic symptoms and the physician who assesses the patient will easily recognize if it is an episode of anaphylaxis.

Once this emergency has been treated, the allergist must be consulted for a complete evaluation and a study to detect the possible causes.

The differential diagnosis of anaphylaxis involves considering all causes of respiratory obstruction and vascular collapse, including pulmonary thromboembolism, cardiac arrhythmias, cardiac tamponade, etc.

How is anaphylactic shock treated?

Anaphylaxis is a medical emergency that requires immediate treatment

The treatment of anaphylactic shock is mainly focused on stabilizing the patient and preventing possible serious complications. Here are the different measures that should be taken to deal with this medical emergency.

Administration of adrenaline

Adrenaline is the drug of choice for the immediate treatment of anaphylactic shock. It is administered by intramuscular injection and acts rapidly to stabilize symptoms. The dose and frequency of administration may vary according to the severity of the allergic reaction and the characteristics of the patient. It is important to always carry an adrenaline auto-injector with you in case of an anaphylactic reaction.

Emergency measures and immediate medical attention

If anaphylactic shock is suspected, it is essential to seek immediate emergency medical attention. While waiting for the medical team, certain measures should be taken to support the patient. This includes lying flat with the legs elevated, loosening any tight clothing, and keeping the airway clear. If the person shows signs of difficulty breathing, supplemental oxygen may be needed.

Medications and adjunctive therapies

Along with the administration of adrenaline, other medications may be used as part of the treatment of anaphylactic shock. These may include antihistamines to reduce the allergic response and corticosteroids to reduce inflammation. In addition, in some cases, adjunctive therapies such as saline nebulization to improve respiratory function and the use of bronchodilators to facilitate breathing may be used. However, it is important to note that these complementary treatments must be indicated by a medical specialist.

Anaphylactic shock and its complications

Anaphylactic shock can trigger a number of serious complications affecting different body systems. It is important to understand and recognize these complications in order to provide appropriate and timely treatment.

Cardiovascular involvement and circulatory problems

  • Cardiac arrhythmias: Anaphylactic shock can cause heart rhythm disturbances such as tachycardia or bradycardia.
  • Arterial hypotension: Severe allergic reaction can lead to a significant drop in blood pressure, which can result in dizziness, fainting and even shock.
  • Heart failure: In extreme cases, anaphylactic shock can cause damage to the heart muscle and trigger heart failure.

Respiratory disorders and breathing difficulties

  • Bronchospasm: The allergic reaction may cause respiratory distress due to constriction of the airways, resulting in bronchospasm.
  • Pulmonary edema: In severe cases of anaphylactic shock, fluid accumulation in the lungs may occur, making breathing even more difficult.
  • Choking: If the allergic reaction is not adequately controlled, it can severely compromise breathing capacity and may lead to asphyxia.

Other possible side effects and complications

  • Digestive difficulties: Anaphylactic shock may cause nausea, vomiting, diarrhea or abdominal pain due to involvement of the digestive system.
  • Skin lesions: Severe allergic reactions may cause hives, intense itching, redness and even blistering of the skin.
  • Neurological problems: In extreme cases, anaphylactic shock can cause neurological disturbances such as seizures or loss of consciousness.

It is essential to be alert to these complications and seek emergency medical attention in case they occur.

Remember that prevention, immediate treatment and proper follow-up are key to avoiding serious and potentially fatal complications.

Where do we treat it?


Department of Allergology
of the Clínica Universidad de Navarra

The Department of Allergy and Immunology of the Clinic is part of the Global Allergy and Asthma European Network, composed of the 25 best departments of Allergy in Europe, chosen for their scientific excellence, multidisciplinary work, teaching and international activities.

We have the most advanced diagnostic techniques, we are at the forefront of research and we collaborate with the best experts. We have more than 50 years of experience in the field.

What diseases do we treat?

Imagen de la fachada de consultas de la sede en Pamplona de la Clínica Universidad de Navarra

Why at the Clinica?

  • More than 50 years of experience.
  • Pioneers in the technique of molecular diagnosis by microarray.
  • Nursing specialized in allergic diseases and their care.

Frequently asked questions about anaphylactic shock

Anaphylactic shock is a medical emergency that requires immediate attention. In case of anaphylactic shock, follow these steps:

  1. Call 911: Immediately call the local medical emergency service (e.g. 112 in Spain).
  2.  Use of Adrenaline: If the affected person has an epinephrine auto-injector, use it immediately.
  3. Position of the patient: Place the person in a comfortable position, preferably lying down and elevating the legs, unless it causes difficulty breathing.
  4. Keep calm: Keep yourself and the affected person as calm as possible and stay with him/her until medical help arrives.
  5. Avoid the offending agent: If possible, avoid continuous contact with the triggering allergen.
  6. CPR if necessary: If the person stops breathing or has no pulse, start cardiopulmonary resuscitation (CPR).

There are several early signs and symptoms that could indicate the development of this serious allergic reaction.

Recognize the precursor symptoms:

  • Intense itching.
  • Skin rash or hives.
  • Swelling of the face, lips, tongue or throat.
  • ng of warmth or flushing.

Identify respiratory symptoms:

  • Difficulty breathing.
  • Wheezing or high-pitched breathing sounds.
  • Sensation of constriction in the throat.

Note digestive symptoms:

  • Nausea or vomiting.
  • Abdominal pain.
  • Diarrhea.

Watch for circulatory changes:

  • Pallor or blueness of the skin.
  • Weak or rapid pulse.
  • Low blood pressure.
  • Dizziness or fainting.

Seek medical attention:

If you recognize these symptoms and suspect someone may be experiencing anaphylactic shock, seek medical help immediately or call emergency services.

There is no specific time duration for anaphylactic shock, as this can vary significantly from case to case.

Rapid Intervention:

With rapid and appropriate medical intervention, including administration of epinephrine and advanced life support, symptoms can improve within minutes to hours.


Even with treatment, the affected person usually needs to be hospitalized to monitor their condition and prevent a biphasic reaction (a second episode of anaphylaxis).

Biphasic reaction:

This reaction can occur up to 72 hours after exposure to the allergen and is a continuation of the initial anaphylactic reaction.

Adrenaline, also known as epinephrine, is the first-line treatment for anaphylactic shock. Its administration is crucial during an episode of anaphylaxis.

Contraction of the bronchial muscles:
Adrenaline relaxes the bronchial muscles, allowing them to open and improve airflow, which is crucial for overcoming respiratory distress.

Acts on the blood vessels, causing them to constrict. This helps to improve blood pressure and reduce swelling and hives.

Prevention of further release of inflammatory mediators:
Inhibits further release of inflammatory and allergic reaction mediator chemicals by mast cells and basophils.

Increased heart rate:
May increase heart rate, which is helpful in situations where the heart is beating very slowly due to the allergic reaction.

Reduced swelling and redness:
By reducing blood flow to affected areas, adrenaline can decrease the swelling and redness associated with the anaphylactic reaction.

The dose of adrenaline (epinephrine) for the treatment of anaphylactic shock depends on factors such as the patient's weight and age, and should be administered according to medical recommendations and established clinical protocols.

Your physician should be the one to indicate the recommended amount in your case.

Adults and Older Children:
Standard Dose for Adults and Children Over 30 kg:
Generally, the dose of auto-injectable epinephrine for adults and children weighing 30 kg or more is 0.3 mg (milligrams).


  • Dosage for Children Between 15 and 30 kg (approximately 3 to 11 years): The usual dose is 0.15 mg.
    Dosage for Children Under 15 kg: Children weighing less than 15 kg, usually under 3 years of age, may require a lower dose, which should be determined and administered by a healthcare professional.

Route of Administration:
Adrenaline is administered by intramuscular injection into the outer thigh and may be administered through clothing if necessary

Additional Dosage:
In some cases, additional doses may be necessary if symptoms do not improve after a few minutes.

Medical Attention:
Immediately after administration of epinephrine, emergency medical attention should be sought, even if symptoms appear to have improved.