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CDHO Advisory: Polycythemia









Use of the dental hygiene interventions of scaling of teeth and root planing including curetting surrounding tissue, orthodontic and restorative practices, and other invasive interventions for persons1 with polycythemia.


Cite as College of Dental Hygienists of Ontario, CDHO Advisory Polycythemia, 2023-06-02


Scaling of teeth and root planing including curetting surrounding tissue, orthodontic and restorative practices, and other invasive interventions (“the Procedures”).





Advanced practice nurses
Dental assistants
Dental hygienists
Health professional students Nurses
Public health departments
Regulatory bodies


To guide dental hygienists at the point of care relative to the use of the Procedures for persons who have polycythemia, chiefly as follows.

  1. Understanding the medical condition.
  2. Sourcing medications information.
  3. Taking the medical and medications history.
  4. Identifying and contacting the most appropriate healthcare provider(s) for medical advice.
  5. Understanding and taking appropriate precautions prior to and during the Procedures proposed.
  6. Deciding when and when not to proceed with the Procedures proposed.
  7. Dealing with adverse events arising during the Procedures.
  8. Keeping records.
  9. Advising the patient/client.


Child (2 to 12 years)
Adolescent (13 to 18 years)
Adult (19 to 44 years)
Middle Age (45 to 64 years)
Aged (65 to 79 years)
Aged 80 and over
Parents, guardians, and family caregivers of children, young persons and adults with polycythemia.


For persons who have polycythemia: to maximize health benefits and minimize adverse effects by promoting the performance of the Procedures at the right time with the appropriate precautions, and by discouraging the performance of the Procedures at the wrong time or in the absence of appropriate precautions.



Terminology used in this Advisory

Resources consulted

Terminology varies among centres.

Polycythemia, the terminology preferred for this Advisory, is a name for a condition which may also be called erythrocytosis. It

  1. refers to three conditions of the blood
    1. primary polycythemia, which
      1. is a rare bone marrow disease
      2. thickens the blood, the consequences of which cause the greatest concern
      3. is of unknown cause
    2. secondary polycythemia, which results from factors
      1. associated with common conditions that lead to oxygen shortage in the blood
      2. independent of the function of the blood-forming stem cells
    3. relative polycythemia, in which decreased plasma volume results in a relative, not absolute, increase in circulating red blood cells.
  2. in some usages refers to a condition of the blood
    1. in which red blood cells, white blood cells, and platelets are abnormally increased
    2. also termed polycythemia vera
      1. in which chiefly red blood cells are abnormally increased
      2. may be termed erythrocytosis.

Other terminology includes

  1. Erythrocytosis, excess of erythrocytes, red blood cells, which occurs in
    1. primary polycythemia
    2. relative polycythemia
    3. secondary polycythemia.
  2. Erythropoietin, hormone produced by the kidney that promotes the formation of red blood cells in the bone marrow.
  3. Gout, inflammation in the joints.
  4. Hematocrit, the percentage, by volume, of the blood that consists of red blood cells; hematocrit = 25 percent means 25 ml of red blood cells in 100 ml of blood.
  5. Hyperviscosity, increase in the resistance of blood to flowing.
  6. Mutation, permanent change in the DNA sequence that makes up a gene; mutations are inherited by a child from a parent or acquired during an individual’s lifetime.
  7. Myeloproliferative disorder, where the bone marrow produces too many cells too rapidly, or produces too few cells.
  8. Neoplastic proliferation, new growth, especially abnormal new growth which produces a tumour, which may be
    1. benign
    2. malignant, which is then called cancer.
  9. Polycythemia vera, alternative terminology for primary polycythemia.
  10. Phlebotomy, bloodletting
    1. in which a predetermined amount of blood, usually half a litre, is removed and replaced with a predetermined amount of intravenous saline solution
    2. which is used in the treatment of primary polycythemia.
  11. Prevalence, the number of people currently suffering from an illness in a given year.
  12. Primary polycythemia
    1. is a type of myeloproliferative disorder
    2. arises when red blood cells are over-produced because of abnormality in the function of the bone marrow caused by mutation, which
      1. occurs in a blood-forming stem cell in the bone marrow
      2. alters a process that governs the growth of the blood cells
      3. is found in more than 90 percent of people with primary polycythemia
      4. is not inherited
      5. is not yet fully understood
    3. may be brought on by tumours in the kidneys because these participate in the regulation of red blood cell production
    4. may result in
      1. total blood volume increasing even to the extent of doubling
      2. hyperviscosity of the blood
      3. plugging of capillaries
      4. generally sluggish flow of blood in the blood vessels.
  13. Secondary polycythemia, occurs
    1. as a physiological response that increases red blood cells that
      1. compensates for lack of oxygen delivery and restores tissue oxygenation to its normal level
      2. compromises circulation because of hyperviscosity when the hematocrit reaches levels higher than 60-65 percent, which
        1. leads to greater tissue hypoxia and EPO secretion
        2. continued increase in red blood cells
        3. further impairment of circulation.
    2. in response to factors or underlying conditions that
      1. are associated with oxygen shortage in the tissues
        1. chronic obstructive pulmonary disease (CDHO Advisory)
        2. chronic heart disease
        3. prolonged lack of oxygen at high altitudes
        4. sleep apnea (CDHO Advisory)
        5. smoking
      2. promote red blood cell production, including
        1. increased production of erythropoietin
        2. kidney or liver tumors
        3. abuse of anabolic steroids or erythropoietin by athletes and bodybuilders
    3. as relative polycythemia, in which an apparent excess red blood cells is due to loss of volume in the liquid portion of the blood, the plasma, arising from
      1. burns
      2. dehydration resulting from
        1. fluid loss
        2. decreased fluid intake
        3. diuretics
      3. hypertension
      4. stress.
  14. Stem cell, capable of development into various cell types during early life and growth; stem cells pertaining to polycythemia exist in the bone marrow where they differentiate into red and white blood cells; see also leukemia (CDHO Advisory).
  15. Thrombophlebitis, swelling and inflammation of a vein caused by a blood clot.
  16. Venesection, alternative terminology for phlebotomy.

Overview of polycythemia

Resources consulted


  1. Primary polycythemia, which
    1. affects 1 to 2 persons per 100,000
    2. has a prevalence of 22 persons per 100,000 people
    3. is first diagnosed at average age of 60 to 65 years of age
    4. seldom occurs below age 40 years
    5. affects men more than women
    6. develops slowly
  2. Secondary polycythemia, which
    1. develops in response to lack of oxygen in the tissues
    2. is associated with common conditions such as heart and lung disease.


  1. Primary polycythemia is usually associated with a gene mutation, the cause of which is unknown.
  2. Secondary polycythemia is usually associated with increased erythropoietin production variously
    1. in response to low blood oxygen level
    2. from an erythropoietin-secreting tumour.

Risk factors

  1. Primary polycythemia risk factors include
    1. age, because it is
      1. most common in adults older than 60
      2. rare in people younger than 20
    2. sex, because it affects men more often than women
    3. family history, because it appears to run in families even though it is not generally inherited
  2. Secondary polycythemia include the risk factors of the underlying cause.

Signs and symptoms

Polycythemia signs and symptoms, which are non-specific, include

  1. orofacial signs
    1. purplish or red areas on the
      1. cheeks
      2. gums
      3. lips
      4. oral mucosa
      5. tongue
    2. spontaneous bleeding of the gums
  2. peptic ulceration of the
    1. esophagus
    2. stomach
    3. upper small intestine
  3. indications of excessive bleeding, such as
    1. nosebleeds
    2. coughing productive blood variously originating in
      1. bronchi
      2. larynx
      3. mouth
      4. trachea
    3. black feces, from intestinal bleeding
    4. menorrhagia
  4. skin problems, variously
    1. bluish colour
    2. itching
      1. especially after a warm bath or shower
      2. after sleeping in a warm bed
    3. burning or tingling sensation in the skin, particularly on the
      1. arms and hands
      2. legs and feet
    4. reddening of the skin, especially on the
      1. face
      2. palms
      3. earlobes
    5. easy bruising
  5. for primary polycythemia, non-specific complaints variously experienced, such as
    • breathing difficulty on lying down
    • chest pain
    • dizziness
    • enlargement of the spleen
    • fatigue
    • feelings of abdominal fullness
    • gout
    • headache
    • hypertension
    • numbness or weakness in the hands, feet, arms or legs
    • shortness of breath
    • visual disturbances

Medical investigation

Polycythemia is considered when physical examination and tests

  1. reveal
    1. hematocrit readings greater than 48 percent in women and 49 to 52 percent in men
    2. hemoglobin levels that are raised
    3. red blood cells and, in some cases, platelets or white blood cells that are increased in number
    4. blood level of oxygen that is below normal
    5. erythropoietin is at abnormal levels
  2. done for another reason reveal abnormalities
  3. may be confirmed by bone marrow sampling
  4. yield a confident diagnosis, which is then differentiated into
    1. primary polycythemia
    2. secondary polycythemia, which involves further investigations for the underlying cause.


  1. Primary polycythemia
    1. controls but does not cure primary polycythemia
      1. aims to
        1. decrease the number of red blood cells and, as a result, the thickness of the blood
        2. prevent excessive bleeding
        3. prevent abnormal clotting
        4. reduce severe itching
        5. reduce the likelihood of complications
      2. includes
        1. phlebotomy, often the first line of treatment, which may also require medications to suppress production of red blood cells because phlebotomy
          1. may increase the number of platelets
          2. does not reduce the size of an enlarged liver or spleen
        2. medications to reduce the risk of blood clots
        3. medications for symptoms
    2. chemotherapy to reduce the number of red blood cells produced by the bone marrow
    3. interferon to lower blood counts
  2. Secondary polycythemia requires treatment of the underlying cause.


  1. Primary polycythemia prevention, because the cause is unknown, is limited to the prevention of complications, comorbidities and associated conditions.
  2. Secondary polycythemia prevention is directed to the conditions to which the polycythemia is secondary.


  1. Primary polycythemia prognosis
    1. for adults who are
      1. untreated reflects survival time of some 18 months for about half of the persons affected
      2. treated reflects survival time of 15 to 20 years for about half of the persons affected
    2. is affected by the
      1. likelihood of diagnosis and therefore treatment in advance of severe symptoms
      2. absence of serious problems following diagnosis and treatment.
  2. Secondary polycythemia prognosis is dependent of that of the underlying cause.

Multimedia and images

Polycythemia vera, bone marrow film

Comorbidity, complications and associated conditions

Comorbid conditions are those which co-exist with polycythemia but which are not believed to be caused by it. Complications and associated conditions are those that may have some link with it. Distinguishing among comorbid conditions, complications and associated conditions may be difficult in clinical practice.

Comorbid conditions, complications and associated conditions for polycythemia include the following.

  1. Hyperviscosity of the blood, which slows the rate of blood flow through blood vessels and in combination with abnormalities in the platelets increases the risk of blood clots, which can cause
    1. thrombosis, which may lead to
      1. heart attack
      2. pulmonary embolism
      3. stroke
      4. vision abnormalities
  2. Hemorrhage
    1. orofacial effects
    2. nose bleeds
    3. from the stomach or other parts of the intestinal tract
    4. indicative of serious complications
  3. Enlarged spleen, caused by the overload of red blood cells that the spleen normally removes from the circulation
  4. Skin problems
  5. High levels of red blood cells, which may lead to
    1. peptic ulceration
    2. gout
    3. kidney stones
  6. Various blood disorders including leukemia.

Oral health considerations

  1. Primary polycythemia is rare, but the occurrence of secondary polycythemia is governed by the factors and conditions to which it is secondary and that, collectively, are not rare.
  2. Primary and secondary polycythemia and their complications, comorbidities and associated conditions have implications for oral healthcare because
    1. precautionary measures, such as blood tests, may be required before oral healthcare is undertaken
    2. close communication and cooperation is required between the treating hematologist and the oral healthcare provider who, for certain oral healthcare interventions, may be a dental specialist
    3. primary and secondary polycythemia may initially present with
      1. spontaneous bleeding from the gums
      2. purplish or red areas on the tongue, cheeks, lips and gums
      3. poor oral hygiene, including
        1. inflamed gingivae
        2. periodontal disease
    4. of the liability of polycythemia
      1. to excessive bleeding from the gums, which requires
        1. attention to the medical history
        2. cautious or conservative use of the Procedures
        3. observation after the Procedures
        4. appropriate advice for the patient/client because bleeding may occur days after the oral healthcare intervention
      2. to formation of blood clots
    5. primary and secondary polycythemia and their complications, comorbidities and associated conditions occur in older persons, who may be subject to factors causing
      1. secondary polycythemia, such as oxygen deficiency caused by
        1. chronic lung disease
        2. heart disease
      2. relative polycythemia, in particular dehydration associated with
        1. decreased fluid intake
        2. diuretics
    6. dental emergencies, which in polycythemia should be avoided as far as possible by preventive oral healthcare.


Sourcing medications information

  1. Adverse effect databases
    Health Canada’s Marketed Health Products Directorate (MedEffect Canada)
    toll-free 1-866-234-2345
    Health Canada’s Drug Product Database
  2. Specialized organizations
    US National Library of Medicine and the National Institutes of Health Medline Plus Drug Information
  3. Medications considerations
    All medications have potential side effects whether taken alone or in combination with other prescription medications, or as over-the-counter (OTC) or herbal medications.
  4. Information on herbals and supplements
    US National Library of Medicine and the National Institutes of Health Medline Plus Drug Information All Herbs and Supplements
  5. Complementary and alternative medicine
    National Center for Complementary and Integrative Health

Types of medications


  1. for reduction of the number of blood cells by
    1. suppressing the bone marrow’s ability to produce blood cells, which may be required in primary polycythemia when phlebotomy is insufficient
      •  anagrelide (Agrylin®), which is used to decrease the number of platelets
      •  busulfan (Myeleran®)
      •  fedratinib (Inrebic®)
      •  hydroxyurea (Droxia®, Hydrea®, Siklos®)
      •  ruxolitinib (Jakafi®)
    2. stimulating the immune system to combat the overproduction of red blood
      •  interferon alfa-2a and alfa-2b injection (Intron A [alfa-2b], Roferon-A [alfa 2a])
  2. for reduction of the risk of blood clots
    •  low-dose aspirin
  3. for symptomatic relief
    1. burning pain in feet or hands
      •  low-dose aspirin, see pain management
    2. bone pain
      •  low-dose aspirin, see pain management
    3. itching; antihistamines, such as
      •  desloratadine (Clarinex®)
      •  fexofenadine (Allegra®)
      •  levocetirizine (Xyzal®)
    4. gastrointestinal symptoms of peptic ulceration; H2 receptor antagonists, such as
      •  cimetidine (Tagamet®)
      •  famotidine (Pepcid®)
      •  nizatidine (Axid®)
      •  ranitidine (Zantac®).

Side effects of medications

  1. See the links to the specific medications listed above.
  2. Pain management with ibruprofen, is used for toothache, but over-the-counter ibruprofen, even for short periods, should be recommended only with medical advice for persons with polycythemia because ibruprofen
    1. is associated with gastrointestinal ulceration, a complication of polycythemia
    2. may counteract the anti-clotting effect of low-dose aspirin, though the evidence of this interaction is somewhat weak.


The dental hygienist in taking the medical and medications histories should

  1. focus on screening the patient/client prior to treatment decision relative to
    1. key symptoms
    2. medications considerations
    3. contraindications
    4. complications
    5. comorbidities
    6. associated conditions
  2. explore the need for advice from the primary or specialized care provider(s)
  3. inquire about
    1. symptoms indicative of inadequate control of polycythemia, such as
      1. bleeding gums
      2. nosebleeds
      3. easy bruising
    2. the patient/client’s understanding and acceptance of the need for oral healthcare
    3. medications considerations, including over-the-counter medications, herbals and supplements
    4. problems with previous dental/dental hygiene care
    5. problems with infections generally and specifically associated with dental/dental hygiene care
    6. the patient/client’s current state of health
    7. how the patient/client’s current symptoms relate to
      1. oral health
      2. health generally
      3. recent changes in the patient/client’s condition.


Identifying and contacting the most appropriate healthcare provider(s) from whom to obtain medical or other advice pertinent to a particular patient/client

The dental hygienist should

  1. record the name of the physician/primary care provider most closely associated with the patient/client’s healthcare, and the telephone number
  2. obtain from the patient/client or parent/guardian written, informed consent to contact the identified physician/primary healthcare provider
  3. use a consent/medical consultation form, and be prepared to securely send the form to the provider
  4. include on the form a standardized statement of the Procedures proposed, with a request for advice on proceeding or not at the particular time, and any precautions to be observed.


Infection Control

Dental hygienists are required to keep their practices current with infection control policies and procedures, especially in relation to

  1. the CDHO’s Infection Prevention and Control Guidelines (2022)
  2. relevant occupational health and safety legislative requirements
  3. relevant public health legislative requirements
  4. best practices or other protocols specific to the medical condition of the patient/client.


The dental hygienist should consult with the primary care physician or hematologist to obtain

  1. clearance for implementing the Procedures (given that this is a blood disorder as per Ontario Regulation 501/07 pursuant to the Dental Hygiene Act, 1991)
  2. advice about
    1. excessive bleeding
    2. complications that may be affected by oral healthcare, such as increased risk of blood clots
    3. possible antibiotic prophylaxis if the patient/client has spleen damage or has had a splenectomy
    4. possible immunosuppression secondary to medications (e.g., ruxolitinib) or treatment modalities (e.g., chemotherapy)
    5. recent changes in medications, under medical advice or otherwise
    6. recently experienced changes in the patient/client’s medical condition.


Dental hygienists are required to initiate emergency protocols as required by the College of Dental Hygienists of Ontario’s Standards of Practice, and as appropriate for the condition of the patient/client.

First-aid provisions and responses as required for current certification in first aid.


Subject to Ontario Regulation 9/08 Part III.1, Records, in particular S 12.1 (1) and (2) for a patient/client with a history of polycythemia, the dental hygienist should specifically record

  1. a summary of the medical and medications history
  2. any advice received from the physician/primary care provider relative to the patient/client’s condition
  3. the decision made by the dental hygienist, with reasons
  4. compliance with the precautions required
  5. all Procedure(s) used
  6. any advice given to the patient/client.


The dental hygienists should

  1. urge the patient/client to alert any healthcare professional who proposes any intervention or test
    1. that he or she has a history of polycythemia
    2. to the medications he or she is taking
  2. should discuss, as appropriate
    1. the importance of the patient/client’s
      1. self-checking the mouth regularly for new signs or symptoms
      2. reporting to the appropriate healthcare provider any changes in the mouth
    2. the need for regular oral health examinations and preventive oral healthcare
    3. oral self-care including information about
      1. choice of toothpaste
      2. tooth-brushing techniques and related devices
      3. dental flossing
      4. mouth rinses
      5. management of a dry mouth
    4. the importance of an appropriate diet in the maintenance of oral health
    5. for persons at an advanced stage of a disease or debilitation
      1. regimens for oral hygiene as a component of supportive care and palliative care
      2. the role of the family caregiver, with emphasis on maintaining an infection-free environment through hand-washing and, if appropriate, wearing gloves
      3. scheduling and duration of appointments to minimize stress and fatigue
    6. comfort level while reclining, and stress and anxiety related to the Procedures
    7. medication side effects such as dry mouth, and recommend treatment
    8. mouth ulcers and other conditions of the mouth relating to polycythemia, comorbidities, complications or associated conditions, medications or diet
    9. pain management.



  1. Promoting health through oral hygiene for persons who have polycythemia.
  2. Reducing the adverse effects, such as excessive bleeding from the gums, by
    1. seeking appropriate medical advice
    2. generally increasing the comfort level of persons in the course of dental hygiene interventions
    3. using appropriate techniques of communication
    4. providing advice on scheduling and duration of appointments.
  3. Reducing the risk of oral health needs being unmet.


  1. Increasing the risk of blood clots as a serious complication by failing to obtain appropriate medical advice.
  2. Performing the Procedures at an inappropriate time, such as
    1. when the patient/client’s polycythemia is at high risk of excessive bleeding
    2. in the presence of unrecognized complications, such as blood clots, for which prior medical advice is required
    3. in the presence of acute oral infection without prior medical advice.
  3. Disturbing the normal dietary and medications routine of a person with polycythemia.
  4. Inappropriate management of pain or medication.






2012-03-01; 2018-11-09; 2023-06-02


College of Dental Hygienists of Ontario, regulatory body
Greyhead Associates, medical information service specialists


College of Dental Hygienists of Ontario


College of Dental Hygienists of Ontario, Practice Advisors


Dr Gordon Atherley
O StJ , MB ChB, DIH, MD, MFCM (Royal College of Physicians, UK), FFOM (Royal College of Physicians, UK), FACOM (American College of Occupational Medicine), LLD (hc), FRSA

Dr Kevin Glasgow

Lisa Taylor

Giulia Galloro

Carolle Lepage


The College of Dental Hygienists of Ontario gratefully acknowledges the Template of Guideline Attributes, on which this advisory is modelled, of The National Guideline Clearinghouse™ (NGC), sponsored by the Agency for Healthcare Research and Quality (AHRQ), U.S. Department of Health and Human Services.

Denise Lalande
Final layout and proofreading

© 2010, 2012, 2018, 2023 College of Dental Hygienists of Ontario


1 Persons includes young persons and children