Herpes Simplex (Cold Sores)—Child Care and Schools

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What is herpes simplex?

  • Herpes simplex is 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; average of 4 days.

  • Contagious period: During the first infection, people shed the virus for at least a week and sometimes for several weeks after signs or symptoms appear. After the first infection, the virus may reactivate from time to time, causing sores on the lips. Recurrent sores shed smaller amounts of virus, lasting 3 to 4 days after signs or symptoms appear. Virus shedding also occurs at lower levels in infected individuals without 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.

Cold (herpes simplex) sore on lip

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Person's lips and chin showing a raised, crusted yellow blister with a pink irregular border about the size of a popcorn kernel over the healthy tissue of the person's top lip.

Cold (herpes simplex) sores on inside of a child's mouth

AMERICAN ACADEMY OF PEDIATRICS

Fingers pull up the top lip of a person's mouth, revealing red and light pink blistering on the inside of one-half of the lip.

How do you control it?

  • Use good hand-hygiene technique at all the times listed in Chapter 2 of Managing Infectious Diseases in Child Care and Schools: A Quick Reference Guide, 7th Edition .

  • 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 or sanitize surfaces that are touched by hands frequently, such as toys, tables, and doorknobs, according to the Routine Schedule for Cleaning, Sanitizing, and Disinfecting in Chapter 8 of Managing Infectious Diseases in Child Care and Schools: A Quick Reference Guide, 7th Edition .

What are the roles of the educator and the family?

  • Report the infection to the staff member designated by the early childhood education program or school for decision-making and action related to care of ill children and staff members. 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 of Managing Infectious Diseases in Child Care and Schools: A Quick Reference Guide, 7th Edition .

Exclude from educational 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 of Managing Infectious Diseases in Child Care and Schools: A Quick Reference Guide, 7th Edition ).

Note: Children and educators with recurrent infection (ie, cold sores) do not need to be excluded as long as there is no drooling.

Cold (herpes simplex) sores on inside of a child's mouth

AMERICAN ACADEMY OF PEDIATRICS

Finger pulls down the lower lip of a child's mouth, revealing a moist inner lip with about 10 grain-sized, fluid-filled, red-bordered blisters.

Readmit to educational setting?

Yes, when all the following criteria are met:

  • When a child with ulcers or vesicles inside the mouth is no longer drooling or, if still drooling, 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 exclusion criteria are resolved, 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.

Comments

  • A very serious eye infection can occur if the herpes simplex virus (from cold sores) is transferred from the hands to the eyes. Practicing good hygiene, especially hand hygiene, is essential.

  • Herpes simplex type 1 usually causes mouth sores, and herpes simplex type 2 usually causes genital sores. However, type 1 can infect the genital area, and type 2 can also infect the mouth.

Disclaimer

Adapted from Managing Infectious Diseases in Child Care and Schools: A Quick Reference Guide , 7th Edition.

The American Academy of Pediatrics (AAP) is an organization of 67,000 primary care pediatricians, pediatric medical subspecialists, and pediatric surgical specialists dedicated to the health, safety, and well-being of all infants, children, adolescents, and young adults.

Any websites, brand names, products, or manufacturers are mentioned for informational and identification purposes only and do not imply an endorsement by the American Academy of Pediatrics (AAP). The AAP is not responsible for the content of external resources. Information was current at the time of publication. 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.

AAP Feed run on: 3/31/2026 Article information last modified on: 3/31/2026