Herpes Simplex (Cold Sores)—Child Care and Schools

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What is herpes simplex?

  • A viral infection that can cause a variety of signs and symptoms in different age groups.

  • In early childhood, herpes simplex most commonly causes blister-like sores in the mouth, around the lips, and on skin that is in contact with the mouth, such as a sucked thumb or finger.

  • Virus is shed by people with or without signs or symptoms (often by adults).

What are the signs or symptoms?

  • During the first or primary infection

    • Fever.

    • Irritability.

    • Tender, swollen lymph nodes.

    • Painful, small, fluid-filled blisters (called vesicles) in the mouth and on the gums and lips.

    • Vesicles weep clear fluid, bleed, and are slow to crust over.

  • After the first infection, subsequent infections may occur with clusters of blisters on the lips, commonly called cold sores or fever blisters.

  • Often, there are no signs or symptoms.

What are the incubation and contagious periods?

  • Incubation period: 2 days to 2 weeks.

  • Contagious period: During the first infection, people shed the virus for at least a week and, occasionally, for several weeks after signs or symptoms appear. After the first infection, the virus may be reactivated from time to time, producing cold sores on the lips. Compared to the first infection, people with recurrent cold sores shed smaller amounts of virus and only for 3 to 4 days after signs or symptoms appear. Virus shedding also occurs at lower levels in infected individuals who have no signs or symptoms.

How is it spread?

  • Direct contact through kissing and contact with open sores.

  • Contact with saliva (eg, from mouthed toys).

  • Can be spread to other areas of the body by scratching or abrading skin after touching an open sore. This is especially problematic in a child with eczema.

How do you control it?

  • Use good hand-hygiene technique at all the times listed in Chapter 2.

  • Avoid kissing or nuzzling children on the lips or hands.

  • Do not share food or drinks between children or staff members.

  • Do not touch sores.

  • Avoid contact with saliva from mouthed toys or objects.

  • Clean toys regularly. (See Chapter 2.)

What are the roles of the teacher/caregiver and the family?

  • Report the infection to the staff member designated by the child care program or school for decision-making and action related to care of ill children. That person, in turn, alerts possibly exposed family and staff members to watch for symptoms.

  • Stress the importance of good hand hygiene and other measures aimed at controlling the transmission of infected secretions (eg, saliva, tissue fluid, fluid from a skin sore).

  • Wash and sanitize mouthed toys, bottle nipples, and utensils that have come into contact with saliva or have been touched by children who are drooling and put fingers in their mouths.

  • Try to avoid touching cold sores with hands, which is difficult but should be attempted. When sores have been touched, careful hand hygiene should follow immediately, using good hand-hygiene technique listed in Chapter 2.

Exclude from group setting?

No, unless

  • The child has ulcers and vesicles inside the mouth and does not have control of drooling.

  • The child is unable to participate and staff members determine they cannot care for the child without compromising their ability to care for the health and safety of the other children in the group.

  • The child meets other exclusion criteria (see Conditions Requiring Temporary Exclusion in Chapter 4).

Readmit to group setting?

Yes, when all the following criteria are met:

  • When a child with ulcers or vesicles inside the mouth is no longer drooling or the ulcers or vesicles have resolved. A child with vesicles (blisters) on the body can return once these areas are covered with clothing or a bandage.

  • When the child is able to participate and staff members determine they can care for the child without compromising their ability to care for the health and safety of the other children in the group.


  • Children and teachers/caregivers with recurrent infection (ie, cold sores) do not need to be excluded as long as there is no drooling.

  • A very serious eye infection can result when people with virus on their hands from cold sores transmit it to their eyes. Good hygiene, especially hand hygiene, cannot be overemphasized.

  • Herpes simplex type 1 is the usual cause of mouth sores, while herpes simplex type 2 is the usual cause of genital sores. At times, type 1 causes infection in the genital area and type 2 causes infection in the mouth.

Adapted from Managing Infectious Diseases in Child Care and Schools: A Quick Reference Guide.

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The information contained in this publication should not be used as a substitute for the medical care and advice of your pediatrician. There may be variations in treatment that your pediatrician may recommend based on individual facts and circumstances.