In-depth

Causes

Symptoms

Anaphylaxis

Anaphylaxis is the most serious type of allergic reaction. It often occurs rapidly after exposure to an allergen and may be life-threatening.

Hives and angioedema

Hives and angioedema — Comprehensive overview covers symptoms, causes, treatment of these common allergic disorders.

Nausea and vomiting

Sick to your stomach? Nausea and vomiting usually pass quickly but sometimes result from long-term or serious conditions.

Shortness of breath

Shortness of breath can be frightening. Most of the time, a heart or lung condition is the cause.

Tachycardia

Tachycardia, a rapid heart rate, is caused by an abnormality in your heart's electrical impulses. Tachycardia can cause serious complications, including sudden cardiac arrest.

Oct. 14, 2011

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