Thomas Dag Horn, MD
Dermatology Physician · Boston, MA
Thomas Dag Horn, MD is a dermatology physician with a practice address in Boston, Massachusetts, and NPI 1275620320, issued on Oct 9, 2006. Check the license on the Massachusetts Board of Registration in Medicine; the Medicare figures below come from public CMS files.
- Name
- Thomas Dag Horn
- Credential
- MD
- Primary taxonomy
- Dermatology Physician 207N00000X
- License number
- E-1269 AR
Self-reported in NPPES; status is on the state search - Practice location
- 55 Fruit St, Boston, MA 02114
- Phone
- (176) 658-9300
- Enumerated
- Oct 9, 2006
- Record last updated
- Sep 16, 2019 (not updated in 7 years: call before relying on the address or phone)
- Medicaid ID
- 131654001 AR
- Medicare enrollment
- Enrolled (PECOS I20070522000102); accepts Medicare assignment
- Medical or professional school
- University Of Virginia School Of Medicine, 1982
- Entity
- Type 1 · individual
8 nearest dermatology physician records → All 627 in Massachusetts → Look up another NPI →
Also registered at 55 Fruit St
A shared address usually means a shared clinic or building; it does not show who employs whom.
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- Megan Abbott, MDAnesthesiology Physician1730839333
- Moustafa AbdallaStudent in an Organized Health Care Education/Training Program1952046062
- Shadi Abdar Esfahani, MD, MPHDiagnostic Radiology Physician1497137590
Verify Thomas Dag Horn in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMassachusetts Board of Registration in MedicineCheck the board
- 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
Bills Medicare through one group practice
- Massachusetts General Physicians Organization IncBoston, MA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Thomas Dag Horn among 627 dermatology physician records in Massachusetts
Thomas Dag Horn, MD is one of 627 dermatology physician records with a practice address in Massachusetts. 83% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2006, is newer than 11% of them.
- NPI issued2006 · 11% of these records are older, 61% newer
- In a Medicare fileYes · 83% of these records are
- In the CMS Doctors and Clinicians fileYes · 71% of these records are
- Graduated1982 · median 2008 among the 445 with a school on file
- Record last updated2019 · 58% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207N00000X and a Massachusetts practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Dermatology Physician providers in Massachusetts
There are 627 dermatology physician records in Massachusetts.
All 627 in Massachusetts → Every provider in Boston → Dermatology Physician nationwide →
The 8 dermatology physician records with the nearest ZIP codes
- Richard Anderson, MDBoston, MA 021141700869831
- Mathew Avram, MDBoston, MA 021141295717296
- Howard Baden, MDBoston, MA 021141427048636
- Melissa Burnett, MDBoston, MA 021141407837818
- Ernesto Gonzalez-Martinez, MDBoston, MA 021141821070806
- Anita Grassi, MDBoston, MA 021141831189513
- Joannes Grevelink, MD PHDBoston, MA 021141538150982
- Joseph Kvedar, MDBoston, MA 021141043200223
Common questions
What is Thomas Dag Horn, MD's NPI number?
Thomas Dag Horn, MD's National Provider Identifier (NPI) is 1275620320, issued on Oct 9, 2006. An NPI identifies a provider in billing; it is not a license.
Where is Thomas Dag Horn, MD located?
The NPPES record lists a practice address at 55 Fruit St, Boston, MA, 02114. Phone: (176) 658-9300. Providers update this record themselves, so call before visiting.
How can I verify Thomas Dag Horn, MD's license?
Search the Massachusetts Board of Registration in Medicine at https://findmydoctor.mass.gov/. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
Source: CMS National Plan and Provider Enumeration System (NPPES), file of Aug 9, 2026 (NPPES files on CMS.gov); NUCC Health Care Provider Taxonomy. Medicare files from data.cms.gov. An NPI identifies who bills; it is not a license.
Figures on PlainDoctor are read from the federal files each page names (CMS NPPES, Medicare Part D, MIPS, Open Payments; the HHS-OIG exclusion list only as counts) and from Census population estimates, with the file date shown beside them. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of Aug 9, 2026.