The symptoms of an anaphylactic reaction may occur within seconds of exposure or be delayed 15 to 30 minutes, or even an hour or more after exposure (typical of reactions to aspirin and similar drugs). Early symptoms are often related to the skin and include
flushing (warmth and redness of the skin),
itching (often in the groin or armpits),
hives.
These symptoms are often accompanied by
a feeling of "impending doom,"
anxiety,
sometimes a rapid, irregular pulse.
Frequently following the above symptoms, throat and tongue swelling results in hoarseness, difficulty swallowing, and difficulty breathing.
Symptoms of rhinitis (hay fever) or asthma may occur, causing
a runny nose;
sneezing, and wheezing, which may worsen the breathing difficulty;
vomiting, diarrhea, and stomach cramps may develop.
About 25% of the time, the mediators flooding the bloodstream cause a generalized opening of capillaries (tiny blood vessels) which results in
a drop in blood pressure,
lightheadedness,
even loss of consciousness.
