By Chris Cole
New research was presented at AAAAI 2019, the American Academy of Allergy Asthma & Immunology Annual Meeting, from February 22-25 in San Francisco. The features below highlight some of the studies emerging from the conference that focused on emergency medicine.
1-Day Aspirin Challenge & Desensitization
Although aspirin challenge and desensitization is the gold standard in diagnosing and treating patients with aspirin-exacerbated respiratory disease (AERD), such approaches can be resource and time intensive. To confirm whether or not oral aspirin challenge and desensitization can be safely performed in an outpatient setting in 1 day, patients with confirmed diagnosis of AERD, stable asthma and baseline FEV1 ≥ 70% of predicted completed both for a study. The starting dose was 40.5mg with escalating doses of aspirin (81, 162.5, 325mg) at 90-minute intervals until symptoms were provoked. Desensitization was defined as tolerating a repeated administration of the provocative dose and at least one subsequent aspirin dose, bringing total aspirin ingested during the in-clinic desensitization to ≥ 325mg. Among participants, 93% completed the challenge and desensitization in 1 day, with an average protocol completion time of 9 hours and 29 minutes. The protocol was chosen to be completed over 2 days by 4.5% of patients, and 2.3% discontinued due to ongoing abdominal discomfort and diarrhea. No participants required epinephrine, emergency department visit, or hospitalization.
Long-Term Opioids in Asthma & Allergic Rhinitis
Previous studies indicate that opioids increase histamine release from mast cells involved in asthma and allergic rhinitis. To determine the percent of patients with asthma or allergic rhinitis with chronic opioid use, study investigators conducted a retrospective chart review of adults from inpatient, emergency, and ambulatory settings. Among those with opioid abuse or dependence, 18% had asthma. There were more males than females in patients with opioid abuse/dependence without asthma (73% vs. 27%) and with opioid abuse/dependence with asthma (56% vs. 44%). Among those with chronic pain conditions, 7% had asthma, and less than 1% had allergic rhinitis. There were more females than males in patients with chronic pain conditions without asthma (64% vs 36%) and with asthma (75% vs 26%). In patients with chronic pain conditions and asthma/allergic rhinitis, 51% had opioid prescriptions, among whom 68% were female.
Predicting Food Allergy Persistence in Early Childhood
Prospectively collected data on the natural history of egg and peanut allergy are lacking. For a study, researchers examined whether skin prick test thresholds or clinical factors present at diagnosis could predict the persistence or resolution of food allergy in early childhood. One-year-olds with challenge-confirmed peanut and egg allergy underwent follow-up—including skin prick test and oral food challenge—at age 6 years. At follow-up, peanut allergy had resolved in 31% of participants, and egg allergy in 89%. Skin prick test measurements at age 1 year was a poor predictor of persistent food allergy at age 6 years, whereas eczema at age 1 was associated with persistence (adjusted odds ratio [aOR] for peanut, 2.74; aOR for egg, 3.53). Tree nut sensitization at age 1 was associated with persistent peanut allergy (aOR, 2.63).
The Effects of GERD & PPIs on RTIs in Asthmatics
Prior research suggests that comorbid gastroesophageal reflux disease (GERD) is significantly associated with poor control among patients with asthma. Other studies indicate that proton pump inhibitor (PPI) treatment does not consistently improve asthma control, while evidence shows that PPIs may increase risk of respiratory tract infections (RTIs). To assess how GERD diagnosis and PPI treatment affect RTI risk and related sequelae in patients with asthma, researchers analyzed data from four large asthma trials. Among children, GERD was found to not increase the rate of RTIs or RTI-related asthma exacerbations. However, PPI use was associated with increased rates of both. In adults, neither GERD nor PPI use affected rates of RTIs or RTI-related asthma exacerbations.
Exhaled Breath Temperature to Monitor Asthma Control
For a study, children diagnosed with asthma attacked performed spirometry, bronchodilator response, fractional exhaled nitric oxide and had—during hospitalization, 1-week follow-up, and 1-month follow-up—had exhaled breath temperature (EBT), peak expiratory flow (PEFR), and asthma score measured daily in order to investigate change in the level of EBT from asthma attack to well-controlled status after discharge. While FEV1 levers were lower at admission than at discharge, EBT levels were higher at admission that at 1-week follow-up and decreased overall during the study period. Within individuals, EBT was decreased, while PEFR increased with time. Furthermore, EBT had a time-dependent dynamic association with PEFR during hospitalization and from asthma attack to stable asthma status. The study authors conclude that “EBT might be a non-invasive and easy-to-use tool to monitor asthma control in children.”
Farm Exposure & Infant Gut Microbiome
Previous studies suggest that farm exposure during infancy is associated with decreased risk of atopic disease, possibly because of different microbial colonization patterns. With the hypothesis that the gut microbiome of infants raised on farms would differ from that of infants not exposed to farms, study investigators analyzed stool specimens collocate at age 2 months from infants from farming families and non-farming families. Gut microbiota of infants raised in farming versus nonfarming environments differed significantly but explained only a small proportion of microbiota compositional variance. Members of the bacterial genera Akkermansia and Clostridia that were found to be enriched in farm infants have been shown previously to be enriched in urban infants at lower risk of atopy and asthma development and are known to reduce inflammation. The study authors suggest that the “differences in neonatal gut microbiome warrant further investigation to delineate how specific early life exposures might modify the gut microbiome to reduce atopic disease.”