Hand, foot, and mouth disease (HFM) almost always starts with a fever, often the only sign for the first day or two. The fever is typically low-grade, and your child (or you) may also feel generally unwell, with a sore throat, reduced appetite, and irritability. The rash and mouth sores that make the disease recognizable don’t show up until later, which is why the earliest stage is easy to mistake for a common cold or strep throat.
The First 24 to 48 Hours: Fever and Sore Throat
The disease begins with a fever that can range from mild to moderate. Along with the fever, you’ll often notice a sore throat, general fatigue, and a loss of appetite. In young children who can’t describe their symptoms, the first real clue is often fussiness and refusing to eat or drink. At this point, there’s nothing visually distinctive about HFM. It looks and feels like any number of viral infections.
This early phase typically lasts one to two days before any visible signs appear. During this window, the virus is already replicating and the person is already contagious.
When Mouth Sores Appear
One to two days after the fever starts, painful sores begin forming inside the mouth. These start as small red spots that develop into tiny blisters, usually smaller than 5 mm, which then break open into shallow ulcers. They tend to appear on the soft palate, the back of the throat, and the tonsils, though they can also show up on the inner cheeks and tongue.
The mouth sores are often the most uncomfortable part of the illness, especially for toddlers. They make swallowing painful, which is why children frequently stop eating and drinking at this stage. If your child was already fussy and off their food during the fever phase, the mouth sores explain why. Drooling more than usual is another common sign that sores have developed inside the mouth.
When the Rash Shows Up
Shortly after the mouth sores appear, a rash develops on the hands and feet. It typically shows up on the palms and soles, which is unusual for most childhood rashes and a helpful way to identify HFM. The rash can also spread to the buttocks, and in some cases to the face, trunk, and limbs.
The rash starts as flat red spots that may progress into small blisters. These blisters are usually not itchy, which helps distinguish them from chickenpox, where itching is a hallmark. In typical cases, the blisters stay small. Atypical presentations can produce larger blisters over 1 cm in diameter that extend beyond the usual palm-and-sole pattern, sometimes appearing on the face (about 41% of atypical cases), buttocks (31%), or trunk (29%).
How HFM Differs From Similar Illnesses
Because HFM starts with a fever and sore throat, parents often wonder if it could be strep throat or another infection. A few details help tell them apart. Strep throat doesn’t produce a rash on the hands and feet, and the throat in strep tends to be bright red with white patches on the tonsils. HFM mouth sores are distinct small blisters that ulcerate, rather than the patchy white coating of strep.
Chickenpox is another common concern. Chickenpox blisters usually start on the scalp, face, or trunk, are intensely itchy, and appear in waves so that blisters, pustules, and crusts all exist at the same time. HFM blisters concentrate on the hands, feet, and mouth, and rarely cause significant itching. Fifth disease (sometimes called “slapped cheek”) starts with a distinctive bright red facial rash that HFM doesn’t produce.
How the Virus Spreads Before You Know It’s HFM
One reason HFM moves so efficiently through daycares and households is that it spreads before anyone recognizes what it is. The virus passes through respiratory droplets when someone coughs, sneezes, or talks. It also spreads through direct contact, like kissing or sharing cups, and through the fecal-oral route, which is common during diaper changes. Contaminated surfaces like doorknobs and toys are another route.
The virus can even spread through improperly chlorinated pool water, though this is rare. Because a child is contagious during that initial fever-only phase, before any telltale blisters appear, the virus often has a head start in group settings.
Mild Cases vs. Severe Cases
Most HFM infections are caused by a virus called Coxsackievirus A16, which produces mild, self-limiting illness. The fever resolves within a few days, the mouth sores heal on their own, and the rash fades without treatment, typically within 7 to 10 days total.
A different virus, Enterovirus 71, can also cause HFM but carries more risk. In outbreaks linked to this strain, about 21% of infected children developed serious complications including neurological problems and heart or lung failure. By contrast, adults infected with Enterovirus 71 were asymptomatic more than half the time, and those who did develop symptoms recovered fully. There’s no way to tell from early symptoms alone which virus is responsible, but the vast majority of HFM cases in the U.S. follow the mild, uncomplicated course.
What to Expect Day by Day
- Days 1 to 2: Fever, sore throat, fatigue, and poor appetite. No visible rash yet.
- Days 2 to 3: Painful mouth sores appear on the soft palate, throat, and tongue. Eating and drinking become difficult.
- Days 3 to 5: Rash appears on palms, soles, and sometimes buttocks or face. Blisters may form.
- Days 5 to 10: Symptoms gradually resolve. Blisters dry and fade. Some children experience nail peeling weeks later, which looks alarming but is harmless and temporary.
Keeping a child hydrated during the mouth-sore phase is the main practical challenge. Cold foods like popsicles and ice chips can soothe the pain and encourage fluid intake. Acidic or salty foods tend to make the sores sting and are worth avoiding until the ulcers heal.