Anaphylaxis
Classification and external resources
Swelling of the face such that the boy is unable to open his eyes. This reaction was due to an allergen exposure.
ICD-10	T78.2
ICD-9	995.0
DiseasesDB	29153
MedlinePlus	000844
eMedicine	med/128
MeSH	D000707

Anaphylaxis is a serious allergic reaction. It begins suddenly and may cause death. Anaphylaxis has many symptoms, such as an itchy rash, throat swelling, breathing problems, and low blood pressure. Common causes include insect bites, foods, and medications.

Anaphylaxis happens when a person eats, breathes in, or is injected with an allergen (something they are allergic to). Their immune system over-reacts. It sends out special proteins from inside certain white blood cells. These proteins can start an allergic reaction or make the reaction worse.