Baby Health 0-12 Months: Common Illnesses & When to Seek Care

Why Do Babies Get Sick So Often?

Babies get frequent infections because their immune systems are still developing and they haven't been exposed to common viruses before. A healthy baby may have 6-8 colds per year in the first two years of life, which is completely normal and actually helps build lifelong immunity.

The first year of life is a critical period for immune system development. When babies are born, they have some protection from antibodies passed from their mother during pregnancy, but this protection gradually wanes over the first few months. Meanwhile, babies are being exposed to a world full of new pathogens for the first time, and their immune systems must learn to recognize and fight each one.

This learning process is essential for building a strong immune system, but it does mean that young babies are particularly vulnerable to infections. Every cold or minor illness is actually helping train the immune system for future challenges. However, because babies' immune systems are immature, infections can sometimes become more serious than they would in older children or adults.

Several factors increase the frequency of infections in infants. Babies who attend daycare or have older siblings who bring home germs from school or playgroups tend to get sick more often. While this can be stressful for parents, research suggests that children who have more infections in early childhood may actually have fewer infections and less risk of allergies and asthma later in life.

The Immune System in the First Year

At birth, babies have a relatively naive immune system that relies heavily on innate immunity - the body's first-line defenses that respond quickly but non-specifically to pathogens. The more sophisticated adaptive immune system, which creates targeted antibodies and "remembers" previous infections, develops gradually throughout childhood.

Breastfeeding provides additional immune protection through antibodies in breast milk, particularly immunoglobulin A (IgA), which helps protect the baby's respiratory and digestive systems. This is one reason why breastfed babies tend to have fewer and less severe infections in their first year of life.

What Are the Symptoms of a Cold in Babies?

A cold in babies typically causes a stuffy or runny nose, sneezing, mild cough, slightly reduced appetite, and mild fussiness. Fever may or may not be present. Symptoms usually last 7-10 days, with the worst congestion occurring around days 3-4.

The common cold is the most frequent illness in infants and is caused by numerous different viruses, with rhinoviruses being the most common culprits. Because there are so many different cold viruses, and immunity to each is temporary, babies can get one cold after another, especially during the fall and winter months.

In young babies, nasal congestion can be particularly troublesome because infants are obligate nose breathers for the first few months of life. This means that a stuffy nose can significantly interfere with feeding and sleeping. You may notice your baby breathing through their mouth, making snorting or snuffling sounds, or having difficulty nursing or taking a bottle because they cannot breathe and suck at the same time.

Most colds resolve on their own within 7-10 days without any specific treatment. However, because young babies cannot blow their noses, they often need help clearing nasal secretions. Using saline drops and a bulb syringe or nasal aspirator before feedings and sleep can provide significant relief.

Home Care for a Baby with a Cold

While there is no cure for the common cold, several measures can help keep your baby comfortable and support recovery. Keeping your baby well-hydrated is important - continue breastfeeding or formula feeding as normal, and offer extra fluids if your baby is over 6 months old. Slightly elevating the head of the crib mattress can help with congestion during sleep.

Using a cool-mist humidifier in your baby's room can help keep nasal passages moist and make breathing easier. Running a hot shower and sitting in the steamy bathroom with your baby can also provide temporary relief from congestion. Avoid over-the-counter cold medicines in babies under 2 years old, as they are not safe or effective for young children.

When a Cold May Be Something More Serious

Most colds are mild and self-limiting, but they can sometimes progress to more serious infections, particularly in young babies. Ear infections, sinus infections, and pneumonia can develop as complications of a cold. RSV (respiratory syncytial virus) often starts like a regular cold but can progress to bronchiolitis, which is more serious.

How Can I Tell if My Baby Has RSV?

RSV (respiratory syncytial virus) starts like a common cold but can progress to more severe symptoms including rapid or labored breathing, wheezing, flaring nostrils, grunting, chest retractions (skin pulling in between ribs), and poor feeding. RSV is most dangerous in babies under 6 months old.

RSV is a very common respiratory virus that causes mild, cold-like symptoms in most children and adults. However, in young babies, particularly those under 6 months old, premature infants, and babies with heart or lung conditions, RSV can cause a more serious lower respiratory infection called bronchiolitis. Nearly all children will have had RSV by their second birthday, but the first infection is typically the most severe.

The infection usually begins with typical cold symptoms: runny nose, mild cough, and possibly a low-grade fever. In most babies, these symptoms improve within a week or two. However, in some babies, the infection moves into the lower airways, causing inflammation and mucus buildup in the small bronchioles of the lungs. This leads to the characteristic wheezing and breathing difficulties associated with bronchiolitis.

RSV season typically runs from November through March in the northern hemisphere, with peak activity in January and February. During these months, parents should be particularly vigilant for worsening respiratory symptoms in young babies.

Warning Signs of Severe RSV

The key to managing RSV is recognizing when a mild cold is progressing to something more serious. Watch for changes in your baby's breathing pattern. Count your baby's breaths for a full minute - more than 60 breaths per minute is concerning. Look for nasal flaring (nostrils widening with each breath), grunting sounds, and chest retractions (the skin between the ribs or below the ribcage pulls in with each breath).

Babies with severe RSV often tire quickly because breathing requires so much effort. They may have difficulty feeding because they cannot coordinate breathing and sucking, and they may produce fewer wet diapers due to decreased fluid intake. Any blue or gray coloring of the lips, tongue, or skin is a medical emergency requiring immediate care.

How Long Does Infant Colic Last?

Infant colic typically begins around 2-3 weeks of age, peaks at 6 weeks, and usually resolves by 3-4 months. The condition is defined by the "rule of threes": crying for more than 3 hours a day, more than 3 days a week, for more than 3 weeks. While extremely distressing for parents, colic is not harmful to the baby.

Colic is one of the most challenging experiences for new parents. The intense, inconsolable crying typically occurs in the late afternoon or evening and can continue for hours despite all efforts to comfort the baby. The baby may pull up their legs, clench their fists, and become red in the face. Between episodes, the baby is completely healthy and feeding well.

The exact cause of colic remains unknown, despite decades of research. Theories include gastrointestinal discomfort from gas or immature digestive systems, overstimulation, and a normal variation in infant crying behavior. What is clear is that colic is not caused by anything parents are doing wrong, and it does not indicate any underlying medical problem in the vast majority of cases.

Colic affects approximately 10-30% of infants, with no difference between breastfed and formula-fed babies. The condition resolves spontaneously by 3-4 months of age in virtually all cases, regardless of what interventions are tried. While this may feel like cold comfort during those difficult weeks, knowing that there is a definite end point can help parents cope.

Strategies That May Help

While no intervention consistently cures colic, various soothing techniques can help reduce crying in some babies. The "5 S's" - swaddling, side/stomach position (for holding, not sleeping), shushing sounds, swinging motion, and sucking on a pacifier - work by mimicking the womb environment and may help calm a colicky baby.

Some parents find that reducing stimulation helps - dimming lights, reducing noise, and limiting visitors during fussy periods. Others find that motion (car rides, stroller walks, gentle bouncing) provides relief. White noise from a fan, vacuum cleaner, or white noise machine can also be soothing for many babies.

For breastfeeding mothers, some studies suggest that eliminating common allergens from the maternal diet (dairy, eggs, wheat) may help in some cases, though the evidence is mixed. For formula-fed babies, switching to a hydrolyzed formula may be worth trying, though this should be discussed with a healthcare provider.

Is Jaundice in Newborns Dangerous?

Mild jaundice is common and usually harmless in newborns, affecting about 60% of full-term and 80% of premature babies. However, severe jaundice can be dangerous if bilirubin levels get too high. Seek immediate care if jaundice appears within 24 hours of birth, spreads to arms and legs, or if your baby is difficult to wake, feeds poorly, or has dark urine.

Jaundice causes the skin and whites of the eyes to appear yellow due to elevated levels of bilirubin, a yellow pigment produced when red blood cells break down. Newborns produce more bilirubin than adults and their immature livers cannot process it as quickly, leading to temporary buildup. This physiological jaundice typically appears on day 2-3 of life and resolves within 1-2 weeks.

In most cases, mild jaundice requires no treatment and resolves on its own as the baby's liver matures and frequent feeding helps eliminate bilirubin through bowel movements. Ensuring your baby feeds frequently and produces regular stools helps the body clear excess bilirubin naturally.

However, very high bilirubin levels can be toxic to the developing brain, potentially causing a serious condition called kernicterus. This is why healthcare providers monitor jaundice carefully in the first days of life and may recommend phototherapy (light treatment) if levels are too high. Risk factors for severe jaundice include prematurity, blood type incompatibility between mother and baby, significant bruising during birth, and poor feeding.

When Jaundice Requires Urgent Attention

Certain types of jaundice require immediate medical evaluation. Jaundice appearing within the first 24 hours of life is always abnormal and may indicate blood type incompatibility or infection. Jaundice that appears or worsens after the first week of life may suggest an underlying problem such as breast milk jaundice (benign) or, rarely, liver disease.

What Causes Common Rashes in Babies?

Common benign rashes in babies include diaper rash, cradle cap, baby acne, milia (tiny white bumps), and erythema toxicum (harmless newborn rash). Most infant rashes require no treatment or simple home care. However, rashes accompanied by fever, lethargy, or that look like bruises require immediate medical attention.

Babies' skin is sensitive and prone to various rashes during the first year of life. Understanding which rashes are normal and which require medical attention can save parents unnecessary worry while ensuring serious conditions are addressed promptly.

Diaper Rash

Diaper rash is perhaps the most common skin condition in infants, affecting nearly every baby at some point. It appears as red, irritated skin in the diaper area and is typically caused by prolonged contact with wet or soiled diapers. The combination of moisture, friction, and the chemical irritation from urine and stool creates an environment that can damage the skin's protective barrier.

Mild diaper rash can usually be treated by changing diapers more frequently, gently cleaning the area with water (avoiding wipes with alcohol or fragrance), allowing time for the skin to air dry, and applying a thick layer of barrier cream containing zinc oxide. Most diaper rash improves within a few days with these measures.

If the rash has bright red areas with satellite lesions (small red dots surrounding the main rash), raised borders, or doesn't improve with treatment, it may be a fungal (yeast) infection requiring antifungal cream. This type of rash is common after antibiotic use and thrives in warm, moist environments.

Cradle Cap (Seborrheic Dermatitis)

Cradle cap appears as thick, yellow, scaly patches on the scalp and sometimes on the face, behind the ears, or in skin folds. It is caused by overactive sebaceous glands, likely due to maternal hormones still circulating in the baby's system. Despite its sometimes dramatic appearance, cradle cap is harmless and not itchy or uncomfortable for the baby.

Cradle cap typically appears in the first few weeks of life and resolves on its own by 6-12 months. Treatment is optional and aimed at improving appearance. Gently massaging the scalp with baby oil or olive oil to loosen scales, followed by brushing with a soft brush and washing with mild baby shampoo, can help remove the scales more quickly.

Other Common Newborn Rashes

Several other rashes are common in newborns and cause no harm. Milia are tiny white bumps, usually on the nose and cheeks, caused by trapped keratin. They disappear on their own within a few weeks. Baby acne appears as small red or white bumps on the face around 2-4 weeks of age and resolves by 3-4 months without treatment.

Erythema toxicum neonatorum sounds alarming but is actually a harmless, common newborn rash. It appears as red blotches with small white or yellow bumps, can appear anywhere on the body, and typically develops in the first few days of life. It requires no treatment and resolves on its own within a week or two.

What Should I Do About Eye Discharge in My Baby?

Yellow or green eye discharge in babies is commonly caused by conjunctivitis (pink eye) from viral or bacterial infection, or by a blocked tear duct. Viral conjunctivitis usually accompanies a cold and resolves on its own. Blocked tear ducts cause persistent watery or goopy eyes and usually resolve by 12 months. Clean discharge gently with warm water and clean cloths.

Eye problems are common in young babies and can cause concern for parents. The most common causes are conjunctivitis (infection of the eye surface) and blocked tear ducts, and it's helpful to understand the difference between them.

Conjunctivitis in babies is often associated with a cold and is usually caused by the same viruses that cause the cold. The eyes become red, watery, and may have yellow or green discharge that causes the eyelids to stick together, especially after sleep. Viral conjunctivitis typically affects both eyes and resolves on its own within 1-2 weeks as the cold improves.

Bacterial conjunctivitis tends to cause thicker, more copious yellow-green discharge and may affect one or both eyes. It may require antibiotic eye drops, so see a healthcare provider if you suspect bacterial infection. In newborns (first month of life), any eye infection should be evaluated promptly, as certain bacteria can cause serious eye damage.

Blocked Tear Ducts

Blocked tear ducts are extremely common, affecting up to 20% of newborns. The tear duct, which normally drains tears from the eye into the nose, may be blocked by a thin membrane at birth. This causes tears to overflow onto the cheeks and collect in the eye, creating a persistently watery or slightly goopy eye.

The good news is that most blocked tear ducts open on their own by 12 months of age. In the meantime, you can massage the tear duct (the small bump at the inner corner of the eye, near the nose) several times a day to help open it, and clean away discharge with warm water. If the duct doesn't open by 12 months, a simple procedure to open it may be recommended.

What Causes White Patches in a Baby's Mouth?

White patches in a baby's mouth are usually caused by oral thrush, a fungal infection caused by Candida. Unlike milk residue, thrush patches don't wipe away easily and may cause feeding difficulties. Thrush is not serious but may require antifungal treatment. It can spread to the mother's nipples during breastfeeding.

Oral thrush is a common yeast infection in babies, caused by an overgrowth of Candida, a fungus that normally lives harmlessly in the mouth and digestive tract. In babies, whose immune systems are still developing, Candida can sometimes overgrow and cause visible white patches on the tongue, gums, roof of the mouth, and inside the cheeks.

The white patches of thrush look like cottage cheese or milk curds, but unlike milk residue, they don't wipe away easily. If you try to remove them, they may leave a red, raw area underneath. Some babies with thrush have no symptoms, while others may be fussy during feeding or refuse to nurse.

Thrush is easily treated with antifungal medication (usually nystatin) applied to the affected areas after feeding. It's important to treat both baby and breastfeeding mother (who may develop thrush on the nipples) to prevent passing the infection back and forth. Sterilizing pacifiers, bottle nipples, and pump parts during treatment also helps prevent reinfection.

When Should I Take My Baby to the Emergency Room?

Seek emergency care immediately for any difficulty breathing, blue or gray skin color, unresponsiveness or extreme lethargy, fever ≥38°C in babies under 3 months, bulging fontanel, seizures, or projectile vomiting. Trust your instincts - if your baby seems seriously ill, seek care even without specific symptoms.

Knowing when your baby needs emergency care can be one of the most anxiety-provoking aspects of new parenthood. While the vast majority of baby illnesses are minor and self-limiting, there are certain warning signs that always require immediate medical attention.

Breathing Difficulties

Any difficulty breathing is an emergency in babies. Signs of breathing problems include: breathing very fast (more than 60 breaths per minute), nostrils flaring with each breath, grunting sounds, skin between the ribs or below the ribcage pulling in with each breath (retractions), or any blue or gray color to the lips, tongue, or skin. Don't drive yourself to the hospital if your baby is having severe breathing difficulties - call emergency services.

Fever in Young Babies

Fever is handled differently in babies depending on their age. For babies under 3 months old, any temperature of 38°C (100.4°F) or higher is a medical emergency requiring immediate evaluation, because young babies can have serious bacterial infections even when they don't look very sick. For babies 3-6 months old, fever warrants a call to your doctor the same day. For older babies, fever alone is less concerning unless accompanied by other worrying symptoms.

Changes in Consciousness or Behavior

A baby who is unusually difficult to wake, limp or floppy, unresponsive, or who has a high-pitched or unusual cry needs immediate medical evaluation. Similarly, any seizure (even if it has stopped) requires emergency care. Babies who refuse to feed, have significantly fewer wet diapers than normal, or seem to be getting progressively sicker should also be evaluated urgently.

How Can I Help Keep My Baby Healthy?

Protect your baby's health through good hand hygiene, keeping up with vaccinations, breastfeeding if possible, avoiding sick contacts, and ensuring smoke-free environments. Regular well-baby checkups allow healthcare providers to monitor development and catch potential problems early.

While it's impossible to prevent all illness in babies - and indeed, some exposure to germs is necessary for immune system development - there are several evidence-based strategies that can reduce the risk of serious infections and support your baby's overall health.

Hand Hygiene

Hand washing is one of the most effective ways to prevent the spread of infection. Wash your hands before handling your baby, before feeding, and after diaper changes. Ask visitors to wash their hands before holding your baby, and avoid contact with people who are sick, especially during flu and RSV season.

Vaccinations

Keeping your baby up to date on recommended vaccinations protects against serious diseases including whooping cough, rotavirus, pneumococcal infections, and others. Vaccines are carefully tested and are one of the most important tools for protecting infant health. Ensure that adults who will be in close contact with your baby are also up to date on their vaccinations, particularly for whooping cough and flu.

Breastfeeding

Breast milk contains antibodies and other immune factors that help protect babies from infections. Breastfed babies tend to have fewer respiratory infections, ear infections, and gastrointestinal illnesses. The WHO recommends exclusive breastfeeding for the first 6 months, with continued breastfeeding along with appropriate complementary foods for up to 2 years and beyond.

Smoke-Free Environments

Exposure to secondhand smoke significantly increases the risk of respiratory infections, ear infections, and SIDS in babies. Keep your home and car completely smoke-free, and avoid taking your baby to places where people are smoking.