anaphylaxis
UK[ˌænəfɪˈlæksɪs]US[ˌænəfəˈlæksɪs]
n
a severe, potentially life-threatening allergic reaction that happens very quickly after exposure to an allergen.
n
a state of extreme sensitivity to a foreign substance, especially a protein, following a previous exposure.
Morpheme Breakdown
ana
phylaxis
ana
again
phylaxis
protection
Etymology
the term 'anaphylaxis' was coined in the early 20th century by french physiologist charles richet. it is constructed from greek elements, but its meaning represents a reversal of the root's original sense. the greek prefix 'ana-' here implies 'again' or 'back', while 'phylaxis' means 'protection'. literally, it suggests 'back protection' or 'against protection'. this paradoxical construction was intentional, describing a state where a second exposure to an antigen does not confer protection (prophylaxis) but instead induces a dangerous hypersensitivity reaction. thus, the word's logic captures the phenomenon's core: a heightened, harmful response upon re-exposure, which is the opposite of the protective immunity one might expect.
Analysis
Structure: ana (again) + phylaxis (protection)
ana- (prefix of Greek origin meaning 'again', 'back', or 'up'); -phylaxis (from Greek 'phylaxis', meaning 'protection', 'guarding').
Examples
the patient went into anaphylaxis after being stung by a bee.
epinephrine is the first-line treatment for anaphylaxis.
food allergies can trigger anaphylaxis, requiring immediate medical attention.