The five illnesses that send children to the doctor most often are the common cold, ear infections, stomach flu, hand foot and mouth disease, and strep throat. Most are caused by viruses, meaning antibiotics won’t help, and nearly every child will encounter several of them before starting school. Here’s what each illness looks like, how long it lasts, and what actually helps your child feel better.
The Common Cold
Young children catch between six and eight colds per year, and kids in daycare may get even more. That number drops as they age and their immune systems build up a library of defenses, but for toddlers and preschoolers, it can feel like one cold rolls directly into the next.
Cold symptoms typically last less than seven days but can linger for up to two weeks. The first few days usually bring a runny nose with clear mucus, sneezing, a mild sore throat, and sometimes a low fever. As the cold progresses, nasal mucus often turns yellow or green. This color change is a normal part of the immune response and doesn’t automatically mean your child needs antibiotics.
Because colds are caused by viruses (rhinoviruses account for the majority), treatment is purely about comfort. Saline nasal drops, a cool-mist humidifier, plenty of fluids, and rest do the heavy lifting. Over-the-counter cough and cold medicines are not recommended for children under six.
Ear Infections
Ear infections are one of the most common reasons children end up on antibiotics. By age three, roughly five out of six kids will have had at least one. They often develop a few days into a cold, when swelling and mucus block the narrow tubes connecting the middle ear to the throat. Fluid gets trapped, bacteria multiply, and pressure builds behind the eardrum.
The hallmark signs are ear pain (tugging or pulling at the ear in babies who can’t yet talk), trouble sleeping, fussiness, and sometimes a fever. You might also notice fluid draining from the ear if the eardrum ruptures, which sounds alarming but usually heals on its own.
Not every ear infection needs antibiotics right away. Current pediatric guidelines recommend immediate antibiotics for children six months and older who have severe symptoms, such as a fever of 102.2°F (39°C) or higher, or moderate to severe ear pain lasting more than 48 hours. For milder cases, especially in children over two, doctors may suggest a “watchful waiting” approach: managing pain for two to three days and starting antibiotics only if symptoms don’t improve. This strategy works because many ear infections clear on their own, and unnecessary antibiotic use contributes to resistance.
Stomach Flu (Gastroenteritis)
Viral gastroenteritis, commonly called the stomach flu, causes vomiting, watery diarrhea, stomach cramps, and sometimes a low fever. Rotavirus and norovirus are the usual culprits in children. The illness spreads easily through contaminated hands, surfaces, and food, which is why outbreaks tear through daycares so quickly.
The vomiting phase is usually the shortest part. It often settles within a day or two, while diarrhea can persist for up to ten days. The real danger isn’t the virus itself but dehydration, especially in infants and toddlers who lose fluids fast relative to their body size.
Watch for these signs of dehydration: a dry mouth and tongue, fewer wet diapers than usual, sunken eyes, cold hands and feet, and unusual sleepiness. If you notice any of these, your child needs medical attention. For mild cases, small frequent sips of an oral rehydration solution replace lost fluids and electrolytes far better than water, juice, or sports drinks. Offer bland foods once the vomiting stops, and don’t worry if your child’s appetite is low for several days.
Hand, Foot, and Mouth Disease
Hand, foot, and mouth disease is extremely common in children under five and spreads rapidly in group settings. It’s caused by a family of viruses, with coxsackievirus being the most frequent. The illness typically starts with a fever, reduced appetite, and a sore throat. Within a day or two, painful sores develop inside the mouth, followed by a rash of flat red spots or small blisters on the palms, soles of the feet, and sometimes the buttocks or legs.
The mouth sores are usually the worst part. They can make eating and drinking painful, so cold foods like popsicles and yogurt tend to go down easier than anything warm or acidic. The illness runs its course in seven to ten days, and there’s no specific treatment beyond pain relief and keeping your child hydrated.
The virus is very contagious, spreading through saliva, blister fluid, and stool. According to CDC guidance, children can return to daycare or school once they have no fever, feel well enough to participate, and don’t have uncontrolled drooling from mouth sores. It’s worth noting that children can shed the virus in their stool for weeks after symptoms resolve, so thorough handwashing after diaper changes remains important long after the rash fades.
Strep Throat
Strep throat is a bacterial infection, which sets it apart from most childhood illnesses on this list. It’s caused by group A streptococcus bacteria and is most common in children between three and fifteen. Unlike a cold-related sore throat, strep typically comes on suddenly with a fever above 100.4°F (38°C), a moderate to severe sore throat, swollen and tender lymph nodes at the front of the neck, and red or pus-covered tonsils. One useful clue: strep throat usually does not come with a cough or runny nose. If your child has both a sore throat and cold symptoms, a virus is the more likely cause.
A throat swab is the only reliable way to confirm strep. Doctors use a scoring system based on the presence of tonsillar swelling, swollen neck glands, fever, and the absence of cough. When three or more of those criteria are present in a child aged three to fourteen, the probability of strep ranges from 32% to 56%, enough to warrant testing but not enough to skip it.
Strep throat does require antibiotics. Treatment shortens the illness, reduces how long your child is contagious, and prevents rare but serious complications like rheumatic fever, which can damage the heart. Most children start feeling better within a day or two of starting treatment and are no longer contagious after 12 to 24 hours on antibiotics.
When Symptoms Need Urgent Attention
Most childhood illnesses resolve at home with rest and fluids, but certain signs indicate your child is struggling to breathe or becoming dangerously dehydrated. These warrant a trip to the emergency room regardless of the underlying illness.
Breathing red flags to look for include: the skin between or below the ribs visibly pulling inward with each breath (called retractions), nostrils flaring open, a grunting sound when exhaling, a whistling or musical sound when breathing, and a bluish tint around the mouth, lips, or fingernails. Excessive sweating with cool or clammy skin, head bobbing with each breath in infants, and a noticeable drop in alertness or responsiveness are also signs that your child’s body is working too hard to get enough oxygen.
For dehydration, the combination of no urine output for eight or more hours, no tears when crying, and sunken eyes or a sunken soft spot on an infant’s head means your child needs fluids faster than you can give them by mouth.