U.S. Allergists Shifted Toward Multispecialty Groups
Key Takeaways
- Across U.S. allergy/immunology practice settings, the allergist workforce rose 10% from 2015 to 2023 while the number of practices with allergists fell 11%.
- Employment shifted toward multispecialty groups over the study period, while solo and allergist-only settings represented smaller shares of allergist employment in 2023.
- Women represented a larger share of U.S. allergists in 2023 than in 2015.
- Average allergist practice size increased over time, and most states showed net movement toward multispecialty groups.
Investigators used Centers for Medicare & Medicaid Services (CMS) Provider Data Catalogs from 2015 and 2023 to identify U.S. allergists and classify practices as solo practice, allergist-only practice, or multispecialty group in the Witt et al workforce analysis in Annals of Allergy, Asthma & Immunology. The comparison also examined state-level changes and a 2023 snapshot by medical school graduation era to describe how allergists were distributed across settings during the study years.
From 2015 to 2023, the number of U.S. allergists increased from 3,108 to 3,417, while the number of practices with allergists fell from 1,782 to 1,585 and employment in multispecialty groups rose from 35% to 47%. Over the same period, solo and allergist-only settings accounted for smaller shares of allergist employment. Taken together, the findings suggest a workforce that became more concentrated across fewer practices.
Women accounted for 35% of allergists in 2015 and 44% in 2023, and a secondary report described an increase in mean allergists per practice, alongside fewer practices and more allergists overall. Most states shifted toward multispecialty groups, with Utah showing the largest increase in allergist numbers and Wyoming the largest decrease. Within the 2023 workforce, more recent medical school graduates were more often working in multispecialty settings and less often in solo practice than earlier graduates.
Investigators said the analysis was limited by the publicly available dataset used, and investigator comments on dataset limits and future workforce analyses also noted that future studies could broaden the picture by including advanced practice providers and all board-certified practicing allergists. These findings describe how the U.S. allergist workforce was organized between 2015 and 2023 and do not establish why consolidation occurred.
In Annals of Allergy, Asthma & Immunology, the analysis described a U.S. allergist workforce that appeared to grow while shifting toward larger, more often multispecialty practice settings, with notable state-to-state variation. The report remains descriptive and does not explain the drivers of those organizational changes.
Clinician Questions
What part of allergy practice does this workforce comparison actually describe?
The comparison describes U.S. allergists identifiable in CMS Provider Data Catalogs at 2 time points and how those physicians were distributed across practice types. It does not report patient-level outcomes, referral performance, or reasons that clinicians entered one practice model rather than another.
How were U.S. allergist practice settings classified in the 2015-to-2023 workforce comparison?
Investigators classified U.S. allergists as working in solo practice, allergist-only practice, or multispecialty group using CMS Provider Data Catalogs from 2015 and 2023. The available abstract and attributed news summary do not report finer operational criteria for those categories.
What does the allergist workforce analysis leave unanswered about practice consolidation in the United States?
The comparison leaves open why U.S. allergists moved into larger groups, because it describes workforce organization across 2 CMS data years rather than the reasons for those changes. Investigators also said the publicly available dataset did not capture the full picture and that future studies could add advanced practice providers and all board-certified practicing allergists.