Diagnosis of Anaphylaxis

The mainstay of diagnosis of anaphylaxis is history and signs and symptoms of anaphylaxis, that appear within minutes of encounter with the material (agent) responsible for anaphylactic reaction. For administration of prompt and appropriate treatment of anaphylaxis, prompt diagnosis based on history and symptoms and clinical examination is essential as life saving measure.

Ideally some medical conditions which may have similar symptoms should be ruled out before diagnosis of anaphylaxis is made, such as complement-mediated immune complex reaction, idiosyncratic (idiosyncrasy is abnormal reaction to an a chemical agent/drug due to genetic setup of some individual) response that may occur with a nonsteroidal anti-inflammatory drug (NSAID, such as aspirin, ibuprofen), or the direct effect of certain drugs or diagnostic agents on mast cells. Generalized urticaria, angioedema, and a sensation of retrosternal oppression along with bronchoconstriction or hypotension (which may or may not be clinically detectable) may be seen with intravenous administration of mast cell degranulation agent or radiographic contrast media and need to be differentiated from anaphylaxis.

In patients with asthma, NSAIDs such as aspirin, indomethacin, mefenamic etc. may cause clinical manifestations such as life-threatening episode of obstruction of upper or lower airways, which can not be distinguished from anaphylaxis. Anaphylaxis like clinical manifestation may also caused by transfusion related reaction, which is due to IgA (immunoglobulin A) deficiency, which is due to complement activation with secondary mast cell participation.

The presence of specific IgE in patients with systemic anaphylaxis can be demonstrated by transferring the patients serum into a normal subject intradermally, which is followed by antigen challenge into the same site in 24 hours. A wheal and flare develop, which is known as the Prausnitz-Küstner reaction.



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