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Anaphylaxis: Causes, Symptoms, Treatment

Medically reviewed by Regina Victoria Boyles, MD · Pediatrics

Written by Nikita Bhalla · Updated Aug 24, 2022

    Anaphylaxis: Causes, Symptoms, Treatment

    Anaphylaxis is a severe hypersensitivity reaction that occurs as a result of exposure to allergens. These are substances that cause allergy. This type of reaction can be almost immediate. It can develop within a couple of minutes to a few hours. It can prove to be life-threatening.

    Diagnosis at the early stages of the medical condition is necessary for efficient treatment. However, the condition often cannot be accurately diagnosed.  

    Definition of Anaphylaxis

    Also called anaphylactic shock and anaphylactic reaction, anaphylaxis is an acute systemic reaction that manifests through symptoms of immediate-type allergic reaction.

    It is characterized by allergies that can cause breathing, airway, and circulatory conditions, largely due to abnormal skin and mucosal changes. It manifests through varied clinical presentations and mechanisms.

    Symptoms of Anaphylaxis

    All the possible symptoms of anaphylactic reaction do not occur to every patient. The symptoms vary from mild and moderate to severe. Anaphylaxis symptoms are as below:

  • Sweating
  • Dizziness
  • Nausea
  • Vomiting
  • Diarrhea
  • Heart palpitations
  • Increased pulse
  • Lightheadedness/Fainting
  • Swelling of the eyes, lips, tongue, and/or throat
  • Itchiness and inflammation of the skin due to hives
  • Difficulty in breathing
  • Wheezing or a sharp noise while inhaling and exhaling
  • Hoarseness of the voice
  • Coughing/Tightness in the chest
  • Pale or bluish skin due to cyanosis
  • Feeling of lump in the throat or throat tightness
  • Confusion in movements
  • Causes

    The immune system specializes in protecting the body from foreign substances and allergens that can cause harm. It reacts to the presence of an allergen by releasing histamine and other chemicals in the blood.

    Allergies are caused due to the presence of these chemicals in the body. Blood vessels also get substantially widened, leading to a sharp drop and a shock to blood pressure levels. 

    The possible triggers of the medical condition and causes for flare-ups of the symptoms are:

    Certain food items: Milk and other milk products, eggs, nuts, grains, fish, food additives, seafood, etc. Food allergies widely vary among individuals.

    Oral and IV Drugs: Medications like antibiotics from the groups of cephalosporin and penicillin may be the reason for allergic reactions amongst some individuals. Others may be allergic to NSAIDs (nonsteroidal anti-inflammatory drugs) like ibuprofen amongst others. Chemotherapy agents like platin drugs, taxanes, opiates, doxorubicin, and monoclonal antibodies.

    Injected agents: Common injected agents that may trigger allergies are lidocaine and procaine. Neuromuscular blocking agents like suxamethonium and vecuronium used during anesthesia are another recognized factor behind allergy triggers.

    Dyes: Dyes used in diagnostic scans and some X-ray procedures are also a well-known cause for triggering allergic reactions.

    Insects: Bites or stings from insects like bees, paper wasps, fire ants, hornets, yellow jackets, etc. 

    Industrial chemicals/materials: Rubber or latex products frequently used by employees of the healthcare industry are another popular trigger for allergies.

    Some of these products are stethoscopes, disposable gloves, catheters, goggles, and dental dams. Other household rubber products include dishwashing gloves, sports equipment, rubber bands, etc.


    The procedure for diagnosis is a combination of physical examination and medical history.

    Let’s take a detailed look at the diagnostic process:

    Physical examination: The doctor will thoroughly check the vital signs and physical symptoms and ask about other manifestations if any. He/she is likely to enquire about the source of the trigger and how long it took for the symptoms to initially manifest themselves. 

    Investigation about medical history: The doctor is expected to ask you about your personal and family history of medical conditions. This will help him/her eliminate the possible medical conditions that are not a part of your genetic history. Being aware of your existing personal medical conditions will also enable him/her to analyze whether they can manifest through symptoms that you are experiencing.

    Also, let your doctor know about the medications that you may be taking currently or have taken in the recent past.

    There are certain medications – oral and intravenous – that may have adverse reactions to cause allergies. Some examples of these are NSAIDs (nonsteroidal anti-inflammatory drugs) like ibuprofen and aspirin. Others include platin drugs, taxanes, opiates, doxorubicin and monoclonal antibodies, cephalosporin and penicillin.

    Remember to take your record of medical prescriptions along, so that your doctor can carefully check whether drug intake has acted as the trigger in your case. 



    The treatment options are as below:

    • Drug injections like epinephrine are often the most recommended treatment. You may also be advised to keep a syringe with this drug handy with you at all times. This will enable you to treat further anaphylactic symptoms like blocked airways as soon as you experience them.
    • Anti-acid (referred to as H2 blockers), corticosteroids like prednisone, and anti-histamine medications. It will altogether help you in averting the risk of suffocation.
    • Patients with symptoms of low blood pressure may be advised oral drugs or intravenous fluids.

    Lifestyle Changes

    Your doctor may advise you to do the following if you have frequent anaphylactic shocks:

    • Avoid allergens that trigger reactions as much as possible. For instance, if you are allergic to a drug, seek medical help immediately. The doctor will either adjust the dose or prescribe a suitable alternative. In case you experience allergic reactions to a certain insect, avoid gardening and exercise caution while visiting forest areas.
    • You may be asked to wear a necklace or a wristband that cautions people of your medical condition.

    Learn more about Allergies here.


    Hello Health Group does not provide medical advice, diagnosis or treatment.

    Medically reviewed by

    Regina Victoria Boyles, MD


    Written by Nikita Bhalla · Updated Aug 24, 2022

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