Allergen immunotherapy improves disease severity in atopic dermatitis
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Subcutaneous and sublingual immunotherapy for aeroallergens improved disease severity and quality of life among patients with atopic dermatitis, according to a review published in The Journal of Allergy & Clinical Immunology.
Based on these findings, treatment for AD would benefit from shared decision-making and a multidisciplinary approach, Derek K. Chu, MD, PhD, assistant professor with the department of medicine at McMaster University, Hamilton, Ontario, Canada, and colleagues wrote.
“Allergen immunotherapy — also called specific desensitization, allergen-specific immunotherapy or hyposensitization — involves the administration of increasing amounts of a specific allergen to an allergic patient to induce tolerance to it,” Chu told Healio.
Subcutaneous immunotherapy (SCIT) and sublingual immunotherapy (SLIT) have been established as safe and effective for addressing allergies to aeroallergens for allergic rhinitis and allergic asthma, Chu said, adding that they also have possible long-term disease-modifying benefits.
“Previous studies of allergen immunotherapy for atopic dermatitis, however, found mixed results,” Chu said. “Therefore, its benefits and harms remain uncertain.”
The study’s design, results
As part of the American Academy of Allergy, Asthma & Immunology/American College of Allergy, Asthma and Immunology Joint Task Force on Practice Parameters 2022 AD guideline update, the researchers reviewed the effectiveness and safety of SCIT and SLIT vs. placebo or standard care for patients with AD.
The researchers examined 23 randomized controlled trials (RCTs) conducted across 13 countries and published through August 2021. These trials included 1,957 adults and children (median of study mean ages, 19 years; range of means, 4-34 years) sensitized primarily to house dust mite with baseline moderate to severe AD treated with allergen immunotherapy (AIT).
In 22 of the RCTs (n = 1,801), the researchers found with moderate certainty that AIT likely improved the probability of reducing the severity of baseline AD by at least 50% compared with not using AIT (40% vs. 25%; RR = 1.53; 95% CI, 1.31-1.78). SCIT and SLIT had similar effects in these trials.
Analysis of eight of the RCTs (n = 629) found with moderate certainty that AIT probably improved Dermatology Life Quality Index scores by four or more points compared with not using AIT (56% vs. 39%; RR = 1.44; 95% CI, 1.03-2.01).
A review of three of the RCTs (n = 113) found with uncertain evidence that AIT may reduce itch by 50% from baseline compared with not using AIT (25% vs. 19%; RR = 1.29; 95% CI, .084-1.98).
Results also showed very uncertain effects of AIT to improve sleep loss (between group mean difference, –0.07; 95% CI, –1.28 to 1.14) and address flares that led to systemic corticosteroid (20% vs. 22%; RR = 0.94; 95% CI, 0.3-2.94).
Incorporating safety data from trials on AIT for allergic rhinitis and asthma, researchers found with high certainty that AIT increased local adverse events (RR = 1.65; 95% CI, 1.48-1.64), primarily at the injection site with SCIT and in the oropharyngeal area with SLIT; with moderate certainty that AIT increased systemic reactions compared with placebo (RR = 1.37; 95% CI, 1.15-1.64); and with moderate certainty that AIT probably increased adverse effects leading to discontinuation compared with placebo (RR = 1.39; 95% CI, 0.94-2.05).
Conclusions, next steps
With moderate certainty, the researchers concluded that AIT improves the severity of AD and the quality of life among patients with the disease, particularly if they are receiving AIT for house dust mites compared with other environmental allergens.
“The relative benefits were similar among SCIT or SLIT, children or adults, and across atopic dermatitis severities,” Chu said.
Chu further noted that SCIT likely and importantly increases adverse events, primarily injection site reactions followed by systemic reactions and adverse events that were important enough to cause discontinuation.
However, he continued, the small increase in adverse events with SLIT, which primarily were transient oropharyngeal reactions, may be unimportant on average.
Also, the impact of immunotherapy on long-term AD control, flares and patient-reported AD severity and the specific domains of itch and sleep quality are less certain.
“The overall evidence is best for immunotherapy to house dust mite rather than other environmental allergens, though the specific species (Der P, Der f or both) and formulations did not modify the effects seen,” Chu said.
Considering the burdens of AIT, including adverse events and time commitments, the researchers said that multidisciplinary care may best achieve optimal AD outcomes.
“This systematic review and meta-analysis provide moderate-certainty evidence that adjunctive AIT results in important improvements in atopic dermatitis severity and quality of life,” Chu said. “This supports a multidisciplinary and shared decision-making approach to optimal atopic dermatitis care.”
These findings will be incorporated into the upcoming AAAAI/ACAAI guidelines on AD as well, Chu said.
“We also will make directed calls for future research, including providing sample size estimates for future RCTs aimed at now open questions to address,” Chu said.
For more information:
Derek K. Chu, MD, PhD, can be reached at chudk@mcmaster.ca.
Perspective
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The results of this analysis appear to support some degree of effectiveness of allergen immunotherapy in the treatment of AD. These results are not fundamentally surprising given the association of AD with other atopic and allergic conditions, which strongly suggest some shared pathologic processes.
This report also raises the possibility of including allergen immunotherapy in the treatment arsenal available for doctors treating AD. The practical applicability will need to be clarified, but given the heterogeneity of AD, a range of different treatment approaches is needed to ensure that patients have successful clinical outcomes.
The major next step in this research would be to evaluate allergen immunotherapy approaches in a real-world setting. Given the potential burden of pursuing this treatment modality, real-world outcomes data would be very useful.
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