Geospatial and insurance barriers to allergist access across the Midwest

Access to allergists in the United States is limited by geographic and insurance-related barriers. The national rate of Medicaid acceptance among allergists was previously reported to be 55.5%, but access across the Midwest has not been characterized.

To measure Medicaid acceptance rates, appointment wait times, and county-level spatial accessibility among allergist-immunologist practices across all 12 US Midwest states.

A telephone survey of 1301 allergist-immunologist practice sites was conducted from July to November 2025. County-level accessibility scores were calculated using a gravity-based 2-step floating catchment area method.

Of the 613 practicing allergists identified, 74.1% accepted Medicaid; only 6.6% offered appointments within 2 weeks. The mean distance to the nearest allergist was 83.6 miles. Counties with whole-county primary care shortage designations had significantly lower allergist accessibility scores.

Insurance status, geographic isolation, and inadequate provider supply create overlapping barriers that disproportionately burden rural and publicly insured patients. Specialty care gaps compound existing primary care deficits. Workforce expansion, Medicaid reimbursement reform, and innovative care delivery models are urgently needed.