Idiopathic anaphylaxis is a perplexing problem that accounts for 30-60% of cases in adults and 10% in children. Idiopathic anaphylaxis occurs without any recognized external trigger. The attacks occur with variable frequency. Symptoms of idiopathic anaphylaxis are rash, hives, swelling around the face, itchy or tingly feeling around your mouth. This can progress to swelling of throat and lips, abdominal pain, nausea, vomiting, difficulty breathing, decrease in blood pressure and shock. It is important to get immediate care of this occurs and to call 911.
There are certain theories on the cause such as hidden allergens, mast cell degranulation, female hormonal effect, sensitivity to histamine and IgE autoantibodies.
Some tests that can be done to help work up the cause are:
1. Skin testing to foods and drugs.
2. Serum testing IgE to foods and drugs.
3. Diagnostic therapeutic trial with prednisone
4. Oral Challenge
5. Tryptase levels
6. Bone marrow examination.
All patients should be advised to avoid taking drugs that may worsen an event. (Beta Blockers, ACE inhibitors, Angiotensin Blockers, MAO inhibitors and tricyclic anti-depressants).
Drugs used to prevent or lessen the severity are, H1 receptor antagonists, albuterol, prednisone and Xolair. Also epinephrine should be prescribed to all patients.
For reasons that are not clear, the vast majority of patients with idiopathic anaphylaxis gradually improve, episodes decline in frequency and remissions occur in many instances.
It is essential that epinephrine be carried at all times and it is the drug of choice for an acute event. Adherence is very important and each patient should be instructed on the proper usage of each type, i.e. Epipen, Auvi-Q and Adrena-click.
A thorough work up of idiopathic anaphylaxis should be made by your allergist or allergy doctor. Hereditary angioedema must also be considered and your allergy doctor can send for testing to work that up.