Causes

• Common causes are allergy to food, medications, insect venom, or latex.
• The most common food allergies in adults are from nuts and seafood. Peanut allergy is the number one food allergy in the USA. In children cow’s milk, egg, wheat, and soy are the common causes.
• Penicillin allergy is the most common cause of anaphylaxis from medications.
• Aspirin and related medications called NSAIDs (non-steroidal anti-inflammatory medications like Motrin, Advil, Aleve) can cause or aggravate the symptoms particularly hives and asthma.
• Sometime dyes used for diagnostic purposes (e.g., with CAT scans or angiograms) can cause an reaction that is very similar to anaphylaxis - that is called an "anaphylactoid reaction." 
• There are five insects in Midwest region whose venom is known to cause anaphylaxis. Those are yellow Jacket (commonest cause), Honey Bee, White faced hornet, Yellow Faced hornet and Wasp.
• Sometimes the cause of anaphylaxis is not found.  

Symptoms

The reaction can range from mild to fatal. A mild reaction involves the skin only in the form of palm and sole itching, generalized itching, hives, and/or lip or eyelid swelling. Sometimes the reaction is progresses to involve the respiratory tract (nose, throat, and lungs) in the form of an itchy, runny nose, excessive sneezing, itchy, red, watery eyes, scratchy throat, cough. The most serious reactions include wheezing, difficulty breathing, low blood pressure, collapse, and sometimes death.

Anaphylaxis is:

• Unpredictable
• Starts suddenly and progresses if not treated promptly. The most severe reactions occur with in the first 20-30 minutes of exposure
• The sooner the reaction is treated with antihistamine and/or Epinepherine (depending on severity) the better it will be controlled.
• Delay in treating this reaction can prove to be fatal.

Treatment:

• First time reaction - go to the nearest medical facility. Call 911 if the reaction is severe.
• Once the reaction is controlled see your family physician or an allergist to uncover the cause and to determine further management.

Cause known:

• Avoid the known cause (e.g., food, medication, or insect). See respective titles for how to avoid.
• ALWAYS carry antihistamine (e.g., Benadryl) and an adrenaline injection (Epipen or Twinject) for emergency use.
• For mild skin reactions, the antihistamine will suffice.
• For a progressive or severe reaction -- especially if there is any difficulty breathing or swallowing -- use the adrenaline injection.

These are FIRST AID ONLY medications. You MUST go to the nearest medical facility for further care. In case of a severe reaction call 911.

Cause unknown:

• Medications and their usage is the same as for a reaction of known cause.
• In case of future reactions, one of the best way to find the cause is to keep a WRITTEN DETAILED food diary going back 12 hours from the time of reaction.
• The doctor can go over the food diary and might be able to pick up the likely cause.

Exercise-induced anaphylaxis (EIA)