Solving the Mystery of Idiopathic Anaphylaxis

Solving the Mystery of Idiopathic Anaphylaxis

Anaphylaxis is a scary and life-threatening immune system response to an allergen. It causes rapid swelling that can make breathing difficult and then impossible. If you or your child has an allergy, you can be prepared by having an epinephrine auto-injector on hand. Imagine if you didn’t know you had to be prepared, if you had an anaphylactic episode without any known allergen.

What is Idiopathic Anaphylaxis?

An anaphylactic reaction without any known trigger, without a known allergen, is called idiopathic. The Most common triggers of anaphylaxis are certain allergens: foods, insect stings and drugs. But, in as many as half of all recurring cases of anaphylaxis, there is no known trigger. A person with this condition may have the reaction at any time, with no warning.

To be diagnosed with idiopathic anaphylaxis (IA), other illnesses have to be ruled out. Skin prick tests can be done to determine a previously unknown allergen, for instance. Other illnesses that may be mistaken for IA include asthma, exercise-induced anaphylaxis, food-dependent exercise-induced anaphylaxis, mastocytosis, hereditary angioedema or panic attacks.

Abnormal Immune Cells May Explain IA

No one yet knows what causes IA, although researchers are working on discovering the underlying triggers. One idea comes from research that found some people with IA have abnormal mast cells. A mast cell is a type of immune cell that contributes to allergic reactions. The abnormality detected in these individuals is a mutation in a receptor on the surface of the cell. The mutation seems to disrupt the normal functions inside the cell.

Researchers from the National Institutes of Health (NIH) found this connection and say there is a strong and telling link between the abnormality and the incidence of IA. The mutation in the mast cells causes abnormal growth, similar to the proliferation of mast cells seen in a condition called mastocytosis. Researchers hypothesize that this mutation also may cause a release of chemicals from the cells that then trigger anaphylaxis.

Ongoing Studies

The link with mast cell mutations is a strong candidate for what may be causing IA in people. However, the research is far from conclusive. The NIH is continuing the study of IA by recruiting participants who suffer from this condition. The participants are receiving either a placebo or a medication over the course of six months to determine the drug’s effect on IA. The researchers hope this will help determine what causes the condition, and that it will lead to the development of effective treatments.

Anaphylaxis is scary enough, but to not know what triggers the life-threatening reaction is even more frightening. Many people who have experienced anaphylaxis have no known allergies causing it, but as researchers continue to investigate IA, it is hoped that answers will be found and a real treatment can be developed.

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