Find a Registered Dental Hygienist


Knowledge Network

FACT SHEET: Chickenpox (also known as varicella; caused by primary infection with varicella-zoster virus [VZV]; not to be confused with shingles/herpes zoster, which results from reactivation of latent varicella-zoster infection from the sensory nerve ganglia of the central nervous system and which usually manifests as a rash along a single dermatome)

Date of Publication: June 14, 2013

Is the initiation of non-invasive dental hygiene procedures* contra-indicated?

  • Yes, if the patient/client is contagious and/or has significant morbidity.

Is medical consult advised?  

  • Yes, if the diagnosis is uncertain and/or the patient/client is not already under medical care. If it is necessary to see a physician, the patient/client should call first to minimize exposure to others.

Is the initiation of invasive dental hygiene procedures contra-indicated?**

  • Yes, if the patient/client is contagious and/or has significant morbidity.

Is medical consult advised? 

  • See above.

Is medical clearance required? 

  • No.

Is antibiotic prophylaxis required?  

  • No.

Is postponing treatment advised?

  • Yes, during the period of communicability (see below).

Oral management implications

  • Mode of transmission is person-to-person via direct contact with vesicle (i.e., blister) fluid or via droplet or airborne spread (typically from coughing or sneezing) of secretions from the respiratory tract. Chickenpox can also spread directly by breathing in virus particles from the fluid of blisters. Indirectly, VZV may be transmitted through articles freshly soiled from discharges from vesicles and mucous membranes of infected persons. This highly communicable disease is contagious to others from up to 5 (usually 1−2) days before the patient/client develops the rash until all the chickenpox blisters have crusted over to form scabs (usually about 5 days after rash onset)1. It takes from 10 to 21 days after exposure to a person with chickenpox or shingles for a non-immune individual (i.e., someone who has never had chickenpox nor received chickenpox vaccine) to develop chickenpox, and thus susceptible individuals should be considered infectious for 10−21 days following exposure. If post-exposure varicella-zoster immune globulin (see below) has been administered, the infectious period may extend to 28 days following exposure. Exposed susceptible health care workers should be excluded from duty during the infectious period.
  • Chickenpox can be prevented by immunization. The National Advisory Committee on Immunization (NACI) recommends that healthy children 12 months to 12 years of age receive two doses of varicella-containing vaccine (univalent varicella or MMRV) for primary immunization. In Ontario’s publicly funded immunization program, univalent varicella vaccine is administered at 15 months of age and MMRV (measles, mumps, rubella, and varicella vaccine) between 4 and 6 years of age. 
  • Non-immune older children, adolescents, and adults should also be considered for vaccination. In particular, varicella immunization should be considered for susceptible women of childbearing age, household contacts of immunocompromised people, healthcare workers (including dental hygienists), adults who may be occupationally exposed, immigrants and refugees from tropical countries (who are more likely to be susceptible to varicella), children and adolescents undergoing chronic salicylic acid therapy, and persons with cystic fibrosis. The varicella vaccine prevents almost all cases of severe disease. Persons with weakened immune systems should only get the varicella vaccine if an infectious diseases specialist supervises them. A simple blood test is available to determine immunity status and hence whether adult immunization is required.  
  • Varicella vaccine is effective in preventing illness or reducing severity if used within 3 days, and possibly up to 5 days, of exposure. It is recommended for susceptible persons following exposure to chickenpox.
  • If a person vaccinated for chickenpox gets the disease (usually a milder form than otherwise would be the case), that individual can still spread it to others. For most people, getting chickenpox once provides life-long immunity. However, for a few people, chickenpox can be contracted more than once, although this is uncommon.
  • If you, the dental hygienist, are pregnant and have never had chickenpox or the varicella vaccine, you should avoid contact with persons with chickenpox or shingles. If you are exposed to varicella-zoster virus and are non-immune, call your physician right away. Varicella-zoster immune globulin (VarIg) is recommended for susceptible pregnant women who have had significant exposure to VZV, but this shot is of maximal benefit in reducing maternal morbidity if administered within 96 hours (and up to 10 days) after first exposure. (It is currently unknown whether VarIg influences fetal outcome.) The live, attenuated varicella vaccine is contra-indicated in women who are pregnant or trying to conceive.

Oral manifestations

  • Small vesicular (blister-like) lesions occasionally involve the oral mucosa, including the buccal mucosa, tongue, gingiva, and palate, as well as the pharyngeal mucosa. The mucosal lesions, which are initially slightly raised vesicles with surrounding erythema (redness), rupture soon after formation and result in small eroded ulcers with a red margin, which resemble aphthous ulcers. The oral lesions are not particularly painful.

Related signs and symptoms

  • Chickenpox usually begins with a low-grade fever, runny nose, sore muscles, and fatigue. One to two days later, an itchy, generalized rash appears, which soon turns into fluid-filled vesicles (blisters). The rash may first appear on the face, chest, and back and then spread to the rest of the body, including inside the mouth, eyelids, and genital area. The fluid-filled vesicles tend to occur in “crops”, so that several stages of old and new lesions will be present at the same time. Headache and decreased appetite may also occur. Unvaccinated children with chickenpox can become covered with hundreds of itchy, sore blisters. If the blisters become secondarily infected, they can result in permanent scars. After about 5 days, the blisters dry out and crust over. Altogether, chickenpox typically lasts between 7−10 days.
  • The signs and symptoms of chickenpox are typically, but not always, attenuated (i.e., milder) in persons in whom vaccination does not completely prevent disease occurrence. 
  • Most children have a relatively mild illness, but severe illness (including death) may occur in infants, adults, and persons with weakened immune systems. Antiviral medications (e.g., acyclovir) may be recommended for people with varicella who are more likely to develop serious disease.
  • Complications from chickenpox include dehydration, otitis media (middle ear infection), secondary bacterial infections of the skin and soft tissues, pneumonia, bleeding problems, blood stream infection (sepsis), toxic shock-like syndrome, osteomyelitis (bone infection), septic arthritis (joint infection), hepatitis (liver inflammation), encephalitis (brain inflammation), cerebellar ataxia (balance and muscular coordination problems due to brainstem dysfunction), and stroke.
  • Pregnant women who contract chickenpox are at risk for serious complications, including severe pneumonia, which may lead to death.
  • If a pregnant woman gets chickenpox in her first or early second trimester, her baby has a small risk of being born with congenital varicella syndrome. In this syndrome, the baby may have abnormalities in limbs, brain, and eyes; scarring of the skin; and low birth weight. Almost one-third of affected infants will die by early in the second year of life. If a woman develops chickenpox from 5 days before to 2 days after delivery, her newborn will be at risk for neonatal varicella, which can result in severe complications and death.
  • Following the initial chickenpox illness, varicella-zoster virus establishes latency in the sensory nerve ganglia, and may reactivate later in life as shingles (herpes zoster).

References and sources of more detailed information

Date: March 13, 2013
Revised: November 18, 2019


1 Vaccinated persons with varicella may develop lesions that do not crust (i.e., papules or macules only); such persons should be isolated until no new lesions appear within a 24-hour period.

* Includes oral hygiene instruction, fitting a mouth guard, taking an impression, etc.
** Ontario Regulation 501/07 made under the Dental Hygiene Act, 1991. Invasive dental hygiene procedures are scaling teeth and root planing, including curetting surrounding tissue.