anaphylactic

[an″ah-fi-lak´tik]

pertaining to or affected by anaphylaxis.

anaphylactic reaction anaphylaxis.

anaphylactic shock a serious and profound state of shock brought about by hypersensitivity (anaphylaxis) to an allergen such as a drug, foreign protein, or toxin. Sometimes it occurs upon second injection of a patient with a previously injected serum or protein.

an·a·phy·lax·is

(an'ă-fi-lak'sis),

An induced systemic or generalized sensitivity; at times the term anaphylaxis is used for anaphylactic shock. The term is commonly used to denote the clinical reaction seen with system IgE-mediated hypersensitivity reaction. Multivalent antigen crosslinks IgE on the surface of tissues mast cells, causing degranulation with release of preformed mediators (for example, histamine). Generation of newly synthesized mediators occurs rapidly. The physiologic manifestations reflect the biologic effects of these mediators. Cutaneous symptoms include pruritus, erythema, urticaria, and angioedema. Respiratory compromise can come from laryngeal obstruction or bronchospasm. Cardiac effects include arrhythmia, hypotension, and shock. The reaction may be fatal if asphyxiation or cardiovascular collapse occurs.

Synonym(s): anaphylactic reaction

[G. ana, away from, back from, + phylaxis, protection]

Farlex Partner Medical Dictionary © Farlex 2012

anaphylactic reaction

An antigen-induced, IgE-mediated release—and production—of chemical mediators, the target of which is blood vessels and smooth muscle.

Clinical findings
Bronchospasm, dyspnoea, hypotension, oedema, shock and possibly death.

Pathogenesis
An anaphylactic reaction is a hypersensitivity type-I reaction which follows re-exposure to an antigen to which the body has previously formed an IgE antibody; within seconds of exposure to the antigen(s) (which may be proteins, polysaccharides and haptens), IgE molecules cross-link on the surface of mast cells and basophils, stimulating vesicle degranulation and release of LBW mediators of anaphylaxis. In the 1º response, preformed molecules are released, including eosinophil chemotactic factor and vasoactive substances (e.g., heparin, histamine, serotonin and various enzymes); in the 2º response, acute-phase reactants are produced and released. Fatal and near-fatal ARs in children are commonly evoked by peanuts, nuts, eggs, milk, fish and others.

Management
Epinephrine as soon as possible.

Mentioned in

References in periodicals archive

* As soon as a patient has an anaphylactic reaction, they should be placed in the supine position with lower extremities elevated; they should not stand up and move as this has been reported to increase the risk of severe anaphylaxis or sudden death.

Severe food allergy and anaphylaxis: treatment, risk assessment and risk reduction

The most common agent involved in intraoperative anaphylactic reactions is muscle relaxant (61-70%); natural rubber latex (NRL) is the second most implicated agent and the incidence of latex-related anaphylactic reactions is increasing despite increasing awareness and preventive measures taken.

Latex allergy on anaesthesiologist and anaesthesia managements: Are the health workers high risk patients?

We carried out this study to determine the effect of G-Tang on the mast cell-mediated anaphylactic reactions in vivo and in vitro murine models.

Effect of Gamiseunggal-Tang on immediate type allergic reaction in mice

(7.) Sampson HA, Mendelson L, Rosen JE Fatal and near-fatal anaphylactic reactions to food in children and adolescents.

Assuring the safety of severely food allergic children in school

Scott Sicherer, an assistant professor of pediatrics at Mountain Sinai School of Medicine and the Jaffe Food Allergy Institute in New York City says "when in doubt, opt for the medication erring on the side of giving epinephrine is better than not giving it (Kritz 2003)." In most cases, the epinephrine fully prevents or reverses an anaphylactic reaction.

Pros and cons of administering epinephrine to campers who are experiencing anaphylactic shock

Adrenaline, in the form of epinephrine, is the best treatment for an anaphylactic reaction, according to FAAN.

Going nuts: why are so many kids allergic?

When the researchers focused on participants who had had an anaphylactic reaction to a sting as children, they found that a later sting induced a similar reaction in only 2 of 43 people who had received the allergy shots but in 7 of 22 people who hadn't.

Curbing allergy to insect venom: therapy stops reactions to stings years later

if he had not had the anaphylactic reaction, in my opinion, he would not have died when he did.'

Death after meal allergy

"There is some thought about there being a refractory period after an anaphylactic reaction, particularly a more severe one, where the patient might not be at risk," commented Dr.

Inadequate anaphylaxis care common in ER

Management of peanut allergies focuses on teaching parents and children to avoid accidental ingestion or exposure to peanuts, how to recognize early symptoms of an allergic reaction, and the treatment of symptoms, especially an anaphylactic reaction (Sampson, 2002).

Peanut allergy: an increasing health risk for children. (Primary Care Approaches)

ACE inhibitors, aspirin, and alcohol each appear to increase the risk for an anaphylactic reaction in adults with food allergies, Dr.

ACE inhibitor allergy alert. (Primary Care: Cardiology)