ImportanceThe rising cost of prescription drugs is a major concern in health care. Specialty medications, particularly biologics, have transformed dermatologic care but are expensive and may be factors in disproportionate growth in spending.ObjectiveTo assess the role of specialty medications in Medicare Part D drug spending among physician dermatologists and dermatology-focused advanced practice clinicians (nurse practitioners and physician assistants) from 2013 to 2022.Design, Setting, and ParticipantsThis economic analysis used Medicare Part D prescriber data on drug prescriptions from 2013 to 2022 to report on prescription drug claims from physician dermatologists and dermatology-focused advanced practice clinicians, identified using validated administrative claims-based definitions. Data were analyzed from December 17, 2024, to May 31, 2025.ExposurePrescription volumes, average prices, and the introduction of new drugs.Main Outcomes and MeasuresThe primary outcome was growth in inflation-adjusted total dermatology drug spending, decomposed by specialty status, prescriptions, prices, and US Food and Drug Administration approval year assessed from Centers for Medicare and Medicaid Services Part D prescriber data from 2013 to 2022.ResultsIn 94 900 359 drug claims from 24 731 dermatology care professionals, inflation-adjusted Medicare Part D spending increased by 16.1% annually, from $768 million in 2013 to $2.95 billion in 2022. Specialty medications contributed 98.4% of this growth, increasing from 30.8% of all dermatology drug spending in 2013 to 80.9% in 2022, despite being only 2.9% of prescriptions. Average inflation-adjusted prices per 30-day prescription for specialty medications increased by 5.1% per year, from $3738 in 2013 to $5872 in 2022. In contrast, prices for nonspecialty medications decreased by 5.3% annually relative to inflation, from $68 in 2013 to $42 in 2022. Most of the growth in specialty medication spending was due to increased prescribing (80.5%) rather than higher prices (19.5%). New therapies approved after 2013 (Otezla, Cosentyx, Taltz, Dupixent, Tremfya, Skyrizi, and Odomzo) accounted for 69.5% of all spending growth. Prescription rates increased more slowly for older specialty drugs (Humira, Enbrel, Stelara, and Erivedge), but their prices increased more (9.2% annually) than prices for newer agents.Conclusions and RelevanceResults of this economic evaluation suggest that specialty medications have become a substantial factor in dermatology drug spending. While the price of the average dermatologic medication has increased rapidly, this primarily reflects increased prescribing of newly introduced specialty drugs. While these therapies expand treatment options, their rising share of costs highlights the need for policies that balance innovation, access, and affordability.