Acute Anaphylaxis: Symptoms and Treatment

Acute anaphylaxis is a systemic allergic reaction (systemic means the entire body is affected). Unlike most allergic reactions, anaphylaxis symptoms are life-threatening and require immediate medical attention. Common anaphylaxis triggers include insect stings and food allergies.

Acute Anaphylaxis Symptoms

With the exception of anaphylactic reactions to medication, acute anaphylaxis symptoms don’t develop with the initial exposure to the allergy-causing substance. After the first bee sting, exposure to food or other allergen, the body’s immune system develops sensitivity to the particular substance. The next time the person is exposed to the allergen is when anaphylaxis symptoms develop.
 
During an acute anaphylaxis attack the body releases histamine in large amounts throughout the body, causing most anaphylaxis symptoms. Acute anaphylaxis symptoms can develop within seconds, although in some cases symptoms don’t develop until hours after the initial exposure to the allergen.
 
Anaphylaxis symptoms include:
  • abdominal cramping
  • abdominal pain
  • anxiety
  • blue skin due to lack of oxygen
  • confusion
  • diarrhea
  • difficulty breathing
  • dizziness, light headedness or fainting
  • facial swelling
  • heart palpitations
  • hives and itchiness
  • nasal congestion
  • nausea or vomiting
  • rapid pulse
  • skin redness
  • slurred speech
  • weakness
  • wheezing/high pitched breathing.
A person suffering acute anaphylaxis finds it difficult to breathe as the histamine response narrows the airways and stimulates the production of mucus. Fluid may accumulate in the lungs and blood pressure drops to a dangerous level. Left untreated the victim may go into shock, lose consciousness and die.
 
In approximately 20 percent of cases, acute anaphylaxis symptoms diminish, only to return with renewed force after two or three hours. Called a biphasic reaction, renewed symptoms are often more severe than the initial reaction.

Anaphylaxis Triggers

In theory, almost any substance could cause anaphylaxis so long as the affected person has an allergic response to said substance. In practice, some substances are more likely to cause acute anaphylaxis than others, including:
  • food (peanuts and seafood are possible triggers)
  • insect stings or bites
  • latex
  • medication (especially penicillin)
  • X-ray dye.
Medications and X-ray dye, unlike other anaphylaxis triggers, may produce symptoms the first time people come into contact with them. This response is not true anaphylaxis but a toxic reaction called the anaphylactoid response. The difference is purely one of medical terminology; anaphylactoid response and acute anaphylaxis have the same symptoms and are treated the same way.
 
Exercise has been known to trigger acute anaphylaxis when combined with certain foods, hot humid conditions or cold temperatures. In some cases anaphylaxis symptoms develop without any known cause.

Risk Factors for Acute Anaphylaxis

Thankfully acute anaphylaxis is relatively rare. People with asthma or allergies appear to have an increased risk of developing anaphylaxis symptoms. People who have had one anaphylaxis reaction have a higher risk of future attacks.

Treating Anaphylaxis

Anaphylaxis is a medical emergency. Without treatment the victim may stop breathing or his/her heart may stop. When this occurs immediate CPR is required.
 
Medications used to treat anaphylaxis focus on restoring breathing while reducing the allergic response. Epinephrine (adrenaline) is administered to the allergic response. Beta agonists may be offered to relieve breathing difficulties, and oxygen administered to aid breathing.
 
Intravenous antihistamines and cortisone may also be used to help improve breathing by reducing inflammation. Steroid medications and antihistamines are also used to prevent the recurrence of anaphylaxis symptoms.
 
If the person experiencing anaphylaxis has had previous attacks, he or she may carry an auto-injector pen that releases medication for anaphylaxis directly into the person’s thigh. Even if this medication is administered, it is essential to seek medical assistance to prevent anaphylaxis symptoms returning as the effects of the medication fade.
 
To aid in breathing, emergency response teams may insert a tube through the nose or mouth into the airway. In other cases medical professionals may insert a tube through an incision in the trachea.

Preventing Acute Anaphylaxis

Avoiding allergens or medication that triggers anaphylaxis symptoms is vital to preventing acute anaphylaxis. Tell your doctor of any allergies when new medication is prescribed. If you have food allergies, be sure you know exactly what ingredients are in the food you eat. Additionally, avoid insect stings or bites by:
  • avoiding bright colored clothing
  • not using perfume or cologne
  • not wearing open shoes or walking barefoot
  • wearing long sleeved shirts and trousers.
If you encounter a stinging insect, move away slowly without swatting the insect.
 
People with a history of anaphylaxis symptoms or severe allergic reactions should wear Meditags or bracelets listing substances that cause reactions. If you are prescribed an auto-injector make sure you and your family members are instructed in the medication’s use. Check the auto-injector on a regular basis to make sure the medication has not passed its expiration date.
 
Resources
 
Food Allergy and Anaphylaxis Network (2006). What is anaphylaxis? Retrieved March 23, 2009, from the Food Allergy and Anaphylaxis Web site: http://www.foodallergy.org/anaphylaxis/index.html.2008.
 
September 5). Anaphylaxis. Retrieved March 23, 2009, from the Mayo Clinic Web site:
http://www.mayoclinic.com/health/anaphylaxis/DS00009.
 
U.S. National Library of Medicine (2008, April 28). Anaphylaxis. Retrieved March 23, 2009, from the MedlinePlus Web site: http://www.nlm.nih.gov/medlineplus/ency/article/000844.htm.