Symptoms
Anaphylaxis is a serious, life-threatening, and generalized hypersensitivity reaction. It usually occurs suddenly and affects various organs. It manifests itself in the following symptoms, among others:
- Respiratory symptoms: difficult breathing, bronchospasm, breathing sounds, coughing, undersupply of oxygen.
- Cardiovascular complaints: Low blood pressure, rapid heartbeat, chest pain, shock, collapse, unconsciousness.
- Skin and mucous membranes: Swelling, rash, hives, itching, laryngeal edema.
- Digestive complaints: Vomiting, diarrhea, abdominal cramps, incontinence.
- Central nervous system: cramps, headaches, anxiety.
In 1-20% of cases, a dangerous so-called biphasic course is observed. This means that a second reaction occurs within 1-72 after recovery. Anaphylaxis is potentially life-threatening and can rarely have a fatal outcome.
Causes
Anaphylaxis can be allergic and nonallergic in cause. Underlying it is often a type 1 allergic reaction due to hypersensitivity to an allergen. It occurs within minutes to hours and results in the release of histamine and numerous other inflammatory mediators from mast cells that cause the symptoms. Possible triggers include, for example:
- Foods: peanuts, fish, nuts, shellfish, milk, eggs, soy.
- Drugs: vaccines, penicillins, muscle relaxants, NSAIDs, monoclonal antibodies, contrast agents.
- Insect bites
- Latex
However, non-allergic triggers are also known, such as cold (see under cold urticaria), heat, UV radiation, certain drugs, alcohol and physical exertion. In so-called idiopathic anaphylaxis, no trigger can be identified.
Diagnosis
The diagnosis is usually made in medical treatment in acute cases on the basis of clinical symptoms and patient history. Numerous other diseases and conditions may be considered as possible differential diagnoses, for example, vasovagal reactions, flushing, poisoning, and other respiratory or cardiovascular diseases.
Prevention
- For prevention, it is recommended to strictly avoid known triggers. Even the smallest amounts can be enough for a severe allergic reaction.
- Good education of those affected.
- Carry an allergy passport or necklace or bracelet with appropriate instructions.
Drug treatment
The triggering allergen should be removed as soon as possible. Epinephrine:
- Epinephrine is the 1st-line treatment. Patients with a known allergy are prescribed a pre-filled epinephrine syringe, which they should always carry with them and self-administer in an emergency for first aid (EpiPen, Jext). For the application there are hardly any contraindications and it is better to use the syringe once too much, rather than too little see under epinephrine ready syringe.
Allergy emergency kit: in many countries is further common the prescription of an allergy emergency kit. It consists of a container with 2 tablets of a glucocorticoid and 2 tablets of an antihistamine. Adults take all 4 tablets of the kit after the onset of the first symptoms see under Allergy Emergency Kit Further care is in the under medical supervision. Anaphylaxis is a medical emergency that always belongs under the supervision of medical professionals. Medications that may be used include epinephrine, beta2-sympathomimetics, oxygen, infusions, vasopressin, glucagon, antihistamines, and glucocorticoids. Immunotherapy (desensitization) remains the only causal drug treatment method to date. The triggering antigens are injected subcutaneously under the skin over a longer period of time. It is not yet possible for all allergies.
