FCAAIA Notes: I have posted many articles on the safety and efficacy of allergy shots.  This report confirms that allergy shots are a very safe treatment.  However, it also addresses the risk of systemic allergic reactions to sublingual (under the tongue, SLIT) tablets and drops.  It is now clear that those treatments also carry risk of severe allergic reactions. There are not large numbers of patients treated and reports yet because of the relative newness of SLIT tablets but by just doing the arithmetic, it is not clear to me that SLIT is all that much safer than subcutaneous immunotherapy (SCIT).  Furthermore anyone who has an allergic reaction to SLIT does so at home, not in a medical office, thereby increasing the risk of a bad outcome. All patients on SLIT should have an epinephrine auto-injector at home.

(Source: March 6, 2017. For Medscape articles: User name: FCAAIA, Password: Allergies)

Infections associated with subcutaneous immunotherapy (SCIT) were nonexistent and systemic reactions were rare in a surveillance study of adverse reactions to SCIT and subcutaneous immunotherapy (SLIT), researchers reported here.

No infections were reported among 1.3 million patients receiving 9.5 million SCIT injections during 2014 and 2015 in the American Academy of Allergy, Asthma & Immunology (AAAAI)/American College of Allergy, Asthma & Immunology (ACAAI) National Surveillance Study, according to Tolly E. Epstein, MD, of Cincinnati Children’s Hospital, and colleagues.

Three fatalities due to systemic SCIT reactions were reported among 46.6 million injections occurring from 2008 to 2015, the authors noted in a presentation at the AAAAI annual meeting.

“During this period we found systemic reactions to SCIT to be relatively stable, although there may have been a spike in very severe reactions in recent years,” Epstein told MedPage Today.

Roughly two-thirds of severe reactions involved patients with asthma, even though only 11% of allergy practices surveyed reported having more than 50% of asthmatics on SCIT, Epstein said.

The findings were based on annual responses from allergists surveyed about their patients SCIT- and SLIT- related systemic reactions of varying severity. From 2008 through 2015, 27% to 51% of AAAAI and ACAAI members participated in the annual surveys.

The data on systemic reactions to sublingual therapy is limited, since the therapy has not been in use for very long, the authors explained. The FDA approved the first oral SLIT medications in 2014, which were indicated for ragweed and grass pollen allergies. A SLIT tablet for the treatment of dust mite allergies won FDA approval last week.

The safety and efficacy of allergy drops is still being established by the FDA, and they are only used off-label in the U.S.

Among 1,355 patients treated with FDA approved SLIT in 2014 and 2015, two grade 3 systemic reactions were reported, with one involving pharyngeal edema and another involving throat tightening and lower respiratory symptoms. Both reactions were treated with epinephrine.

The FDA recommends that all patients taking SLIT have an epinephrine auto-injector on hand because the self-administered allergy immunotherapy can result in systemic allergic reactions and even life-threatening anaphylaxis.

A recently published analysis of outcomes data among patients on SLIT found reactions requiring epinephrine to be uncommon.

Epinephrine administrations in 13 timothy grass, five ragweed, and 11 house dust mite (HDM) SLIT-tablet trials were evaluated in the trial. Epinephrine auto-injectors were supplied to participants in most of the trials conducted in North America, but not in the European or Japanese trials.

The epinephrine administration rate for SLIT-tablet-related events was 0.2% administrations/person (1.80 administrations per 100,000 SLIT-tablets) in the trial, based on results from a 2016 study.

In the grass SLIT-tablet trials, epinephrine was used eight times for grass SLIT-tablet–related adverse events: four times for systemic allergic reactions and four times for local mouth and/or throat swelling.

In the ragweed SLIT-tablet trials, epinephrine was used four times for ragweed SLIT-tablet-related adverse events: one time for systemic allergic reaction and three times for local mouth and/or pharynx/throat swelling.

In the dust mite SLIT-tablet trials, epinephrine was administered four times -tablet–related adverse events: one time for systemic allergic reaction and three times for local events.

Of the 16 epinephrine administrations for events related to SLIT-tablet treatment, 11 occurred within the first week of treatment. All of the SLIT-tablet-related events requiring epinephrine were treated successfully with no further complications.

“We are just beginning to get real-world data on SLIT, and while it appears that reactions are uncommon, there is some risk for having systemic reactions,” Epstein said. “Even potentially severe ones.”

Mary Beth Fasano, MD,of the University of Iowa Children’s Hospital in Iowa City, told MedPage Today said research is needed to identify patient characteristics associated with a higher risk for adverse reactions to SLIT therapy. Fasano was not involved with the study.

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