Entopy: Up to 40% of patients with idiopathic rhinitis have locally produced IgE

Local IgE has been found in a variety of tissues, including nasal and bronchial mucosa. IgE is produced in these local tissues and not simply the product of migration to the tissue from regional lymphoid tissue or blood.

Local IgE has been identified in most of both atopic and nonatopic asthmatic patients and allergic rhinitis patients.

Up to 40% of patients with idiopathic rhinitis (IR) and a positive nasal provocation test result have evidence of locally produced IgE, which has been coined entopy.

There are a large number of IR patients for whom current treatment regimens are suboptimal. The concept of local allergy in IR patients is both intriguing and controversial.

Studies have reported conflicting results, and currently there is no single best test to evaluate for entopy.

References

Local production of IgE in the respiratory mucosa and the concept of entopy: does allergy exist in nonallergic rhinitis? Forester JP, Calabria CW. Ann Allergy Asthma Immunol. 2010 Oct;105(4):249-255. Epub 2010 Apr 14.
Nonallergic rhinitis, CCJM 2012 review.
Image source: Illustration for "Aquiline or Roman Nose", Wikipedia, GNU Free Documentation License.

Comments from Twitter

Nathan Hare M.D. @AllergyTalk: Nonallergic rhinitis: Common problem, chronic symptoms. Great Discussion bit.ly/HbYikn #allergy

@Allergy Not so impressed with CCJM review of NAR bit.ly/HbYikn - Barely mentioned local AR - may affect 40% of NAR. A big miss in the CCJM review... 40% of patients with NAR may have locally produced IgE bit.ly/I8Vxid

@AllergyTalk: the actual % is lower- I looked at your reference- it is actually 40% of pts who have NAR & pos intranasal challenge

@Allergy: I was waiting for your tweet on that...:) No one knows the actual prevalence yet - see here: bit.ly/Hie3Ft

@AllergyTalk: good point- I have actually started wondering about that when talking to pts about " chronic" rhinitis. I agree though- it will prob be a fair amt of the "non-allergic" rhinitis pts.  I now routinely include a discussion of local IgE prod with my pts with rhinitis and neg skin &/or IgE titers.

@Allergy: right, that's the point... It seems like a lot a of NAR have local AR, hot research topic, but mentioned in 1 sentence in CCJM

@AllergyTalk:  I read it quickly during the workday and liked the NAR discussion, but completely missed they left out the local IgE info. They also split NAR into so many subtypes it made my head hurt- I don't have time to sub sub classify chronic rhinitis each time.

Dr. Ellis @DrAnneEllis: It's always in the differential for sure and I tell my px's of that possibility also. Wish it were easier 2 prove :)

@AllergyTalk: They should design a test like the rapid strep test looking for allergen spec IgE in snot after nasal challenge

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