Herpangina is a viral illness that causes a high fever and small, blister-like sores inside the mouth and throat. It primarily affects children under 10 and, despite its alarming appearance, typically resolves on its own within 7 to 10 days. The name sounds similar to herpes, but the two are caused by completely different viruses.
What Causes Herpangina
Herpangina is caused by a group of viruses called enteroviruses, most commonly coxsackievirus A. Several other enterovirus strains can also trigger it, which is why a child can get herpangina more than once. The virus spreads through direct contact with saliva, nasal discharge, or fluid from the blisters, and also through the fecal-oral route, which is especially common in daycare settings where diaper changes happen frequently.
Cases peak during summer and early fall in temperate climates, though in tropical regions they can occur year-round. The virus is highly contagious during the first few days of illness, but children can continue shedding the virus in their stool for several weeks after symptoms clear.
How It Looks and Feels
The illness usually starts suddenly with a fever, often high, sometimes reaching 104°F (40°C) or above. Within a day or two, small grayish-white blisters appear on the soft palate, tonsils, and the back of the throat. These blisters break open quickly to form shallow, painful ulcers surrounded by a red ring. Most children develop anywhere from 2 to 12 of these sores.
Because the sores sit in the back of the mouth and throat, swallowing becomes painful. Young children may refuse to eat or drink, drool more than usual, or become unusually fussy. Some children also develop a sore throat, headache, neck pain, or mild respiratory symptoms like a runny nose. About 75% of children with herpangina develop a fever, and temperatures tend to run higher than in many other childhood viral illnesses.
The fever typically breaks within 2 to 4 days. The mouth sores take a bit longer, usually healing completely within a week without scarring.
Herpangina vs. Hand, Foot, and Mouth Disease
These two conditions are closely related, caused by overlapping groups of enteroviruses, and they’re easy to confuse. The key difference is where the rash shows up. Herpangina causes sores only inside the mouth and throat. Hand, foot, and mouth disease (HFMD) also produces oral sores but adds a vesicular rash on the palms, soles of the feet, and sometimes the buttocks.
Herpangina also tends to produce higher fevers. In one study comparing the two, nearly 78% of herpangina patients developed a fever compared to about 48% of HFMD patients, and the temperatures in herpangina ran significantly higher. Sore throat was also more common with herpangina. If your child has mouth sores but no rash on the hands or feet, herpangina is the more likely diagnosis.
How It’s Diagnosed
Doctors diagnose herpangina by looking inside the mouth. The combination of a sudden high fever plus small blisters or ulcers concentrated on the soft palate and back of the throat is distinctive enough that lab tests are rarely needed. Blood work or viral cultures may be ordered in unusual cases, such as when symptoms are severe or the child has a weakened immune system, but for the vast majority of children, it’s a straightforward visual diagnosis.
Treatment and Home Care
There’s no antiviral medication for herpangina. Because it’s caused by a virus, antibiotics won’t help either. Treatment focuses entirely on managing fever, easing pain, and preventing dehydration.
Managing Fever and Pain
For fevers above 101.3°F (38.5°C), ibuprofen or acetaminophen can bring the temperature down and reduce mouth pain at the same time. Cool compresses on the forehead or a cooling patch can also provide some comfort. Notably, topical numbing gels and sprays containing lidocaine or diphenhydramine are generally not recommended for the mouth sores in herpangina, as they carry risks in young children and the sores heal on their own.
Keeping Your Child Hydrated
Hydration is the single most important part of home care. The mouth sores make drinking painful, and young children with high fevers lose fluid quickly. Offer cool or room-temperature liquids frequently in small amounts. Popsicles, ice chips, and cold smoothies can soothe the throat while getting fluids in. Avoid anything hot, spicy, acidic (like orange juice), or crunchy, as these will irritate the sores.
Stick to soft or liquid foods that are easy to swallow: yogurt, applesauce, mashed bananas, broth, and similar options. Rinsing the mouth with salt water after meals helps keep the sores clean and can reduce discomfort. For babies and toddlers too young to rinse, gently wiping the inside of the mouth with a cloth dipped in salt water serves the same purpose.
If your child is producing fewer wet diapers than usual, has no tears when crying, or seems unusually lethargic, dehydration may be setting in. Electrolyte solutions designed for children can help, and persistent signs of dehydration warrant a call to your pediatrician.
When Children Can Return to School or Daycare
CDC guidelines for enteroviral illnesses like herpangina and HFMD recommend that children can return to group settings once they have no fever, feel well enough to participate, and don’t have uncontrolled drooling from mouth sores. In practice, this usually means keeping a child home for about 3 to 5 days. Some local health departments may require longer exclusion periods during outbreaks.
Because the virus can shed in stool for weeks, good hand hygiene, especially after diaper changes and bathroom trips, remains important even after a child looks and feels completely better.
Rare but Serious Complications
The overwhelming majority of herpangina cases resolve without any lasting effects. Dehydration from poor fluid intake is the most common complication and is almost always preventable with attentive home care.
In very rare instances, the enteroviruses behind herpangina can affect the nervous system or heart. A large South Korean study tracking hospitalized cases of herpangina and HFMD over five years found that severe neurological complications, including brain inflammation, paralysis-like syndromes, and heart-lung failure, did occur but were uncommon. Seizures were the most frequently reported neurological symptom among severe cases. Most patients recovered fully, though a small number (about 5% of the severe hospitalized cases in that study) experienced lasting effects or death, nearly all involving cardiopulmonary complications.
These outcomes are extremely rare in the context of how common herpangina is overall. Signs that warrant immediate medical attention include a very high fever that doesn’t respond to medication, a stiff neck, persistent vomiting, difficulty breathing, unusual drowsiness, or seizures.