Mark Thomas O'Hollaren, M.D.
Allergy Physician · Portland, OR
Mark Thomas O'Hollaren, M.D. is an allergy physician with a practice address in Portland, Oregon, and NPI 1588723787, issued on Dec 6, 2006. Check the license (Oregon 13450, as entered in NPPES) on the Oregon Medical Board; the federal record below is the public data PlainDoctor holds for this provider.
- Name
- Mark Thomas O'Hollaren
- Credential
- M.D.
- Primary taxonomy
- Allergy Physician 207KA0200X
- License number
- 13450 OR
Self-reported in NPPES; status is on the state search - Practice location
- 511 SW 10TH Ave, Portland, OR 97205
- Phone
- (503) 228-0155
- Enumerated
- Dec 6, 2006
- Record last updated
- Jul 8, 2007 (not updated in 19 years: call before relying on the address or phone)
- Fax
- (503) 226-8342
- Medicaid ID
- 167155 OR
- Entity
- Type 1 · individual
Also registered at 511 SW 10TH Ave
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Kyra Ahlstrom, LMTSpecialist1649577073
- Douglas Ainslie, DMD MSOrthodontics and Dentofacial Orthopedics Dentistry1205961570
- Liu AnAcupuncturist1326112087
- Genevieve Arnaut, PSYD, PHDPsychologist1255547113
- Jennifer Bane, PA-CMedical Physician Assistant1033437298
- Gemma Baumer, MA, LPC-INTERNProfessional Counselor1073199956
Verify Mark Thomas O'Hollaren in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersOregon Medical Board
Search for license 13450Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
Allergy Physician providers in Oregon
There are 10 allergy physician records in Oregon. No Medicare prescribing, quality score, industry payment or hospital affiliation is published for this NPI.
Other allergy physician records in Oregon
- Laurel Anderson Cowell, MDPortland, OR1356346217
- Alice Chou, MDEugene, OR1508802521
- Joel Depper, M.D.Bend, OR1194733519
- Edward Kerwin, M.D.Medford, OR1568465847
- Kevin Kral, M.D.Bend, OR1134100092
- Kevin Parks, M.D.Medford, OR1467499475
- Candice Rohr, MDEugene, OR1326084344
- Robert Schwartz, MDPortland, OR1568482610
- Anita Tam Su, MDPortland, OR1891905261
Common questions
What is Mark Thomas O'Hollaren, M.D.'s NPI number?
Mark Thomas O'Hollaren, M.D.'s National Provider Identifier (NPI) is 1588723787, issued on Dec 6, 2006. An NPI identifies a provider in billing; it is not a license.
Where is Mark Thomas O'Hollaren, M.D. located?
The NPPES record lists a practice address at 511 SW 10TH Ave, Portland, OR, 97205. Phone: (503) 228-0155. Providers update this record themselves, so call before visiting.
How can I verify Mark Thomas O'Hollaren, M.D.'s license?
NPPES lists Oregon license number 13450, as entered by the provider. Search the Oregon Medical Board at https://www.oregon.gov/OMB/Pages/default.aspx. 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. 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.