Provider records sourced from NPPES (CMS National Plan & Provider Enumeration System). Data current as of August 10, 2026.
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Dr. Mark Thomas O'Hollaren, MD

Individual provider Allergy Physician · NPI 1588723787

Dr. Mark Thomas O'Hollaren, MD is an Allergy Physician in Portland, Oregon. Licensed in Oregon. Registered with an NPI since 2006.

Licensed in
OR
In the registry since
2006
What do these letters mean?
MD — Doctor of Medicine
A physician who completed allopathic medical school.

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Practice location Address checks out

511 SW 10th Ave Ste 1301
Portland, OR 97205-2732
Phone: (503) 228-0155
Fax: (503) 226-8342
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Pin is approximate — placed at the ZIP-code centre, not the exact door.

Specialties & licences

Allergy Physician (primary) Taxonomy 207KA0200X · Licence 13450 (OR)

Record details

NPI number1588723787
Entity typeIndividual (Type 1)
GenderMale
Credentials MD
Sole proprietorNo
NPI enumeratedDecember 6, 2006
Last updated in NPPESJuly 8, 2007

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