Common Acute Illness in Babies and Young Children

Babies and young children commonly develop fever, coughs, vomiting, diarrhoea, rashes and ear or throat symptoms. Most episodes improve without serious complications. A small proportion of children become seriously unwell. The priority is therefore recognising deterioration and obtaining the right level of care, not naming the illness at home.

Young children can be difficult to assess Babies cannot describe pain, breathlessness, dizziness or confusion. Young children may become quiet, irritable or clingy during many different illnesses. A child's condition can also change between observations. The most useful information often includes age, breathing, colour, alertness, feeding and drinking, urine output, movement, the direction of change, and what the parent or carer notices is different. One normal observation does not exclude serious illness. One abnormal symptom does not always identify its cause. Age changes risk The younger the baby, the lower the threshold for clinical assessment. Newborns and young infants may have serious infection without obvious localising symptoms. They may not develop a high fever. Poor feeding, temperature instability or reduced responsiveness may be the main signs. NHS guidance notes that babies younger than 6 months can be difficult to assess remotely. A parent or carer who is very worried should seek face to face assessment rather than relying only on telephone reassurance. Fever is a sign, not a diagnosis A fever is a raised body temperature, commonly caused by the immune response to infection. Fever itself does not identify whether the cause is viral, bacterial or non infectious. The height of the temperature does not reliably measure severity in older infants and children. A child with a moderate fever can be seriously ill. Another child with a higher temperature may remain alert and well hydrated. Age, behaviour, breathing, circulation and associated symptoms are more informative. Measuring temperature For children younger than 5 years, an electronic thermometer in the armpit is commonly recommended for home use. The reading should be taken according to the manufacturer's instructions. Touching the forehead can suggest that a child feels hot but does not provide an accurate measurement. A recent bath, heavy clothing or a warm room can temporarily affect temperature. The child's clinical condition remains important even when a thermometer reading is normal. Important age specific thresholds A temperature of 38°C or higher in a baby younger than 3 months places the baby in a high risk group for serious illness. This requires urgent clinical assessment. A temperature of 39°C or higher in a baby aged 3 to 6 months is an intermediate risk feature requiring prompt assessment in context. These thresholds do not mean lower temperatures are always safe. A baby who appears seriously unwell needs assessment regardless of the recorded temperature. The NICE traffic light system NICE uses a traffic light system to help healthcare professionals assess feverish children under 5. It groups observed features into green (low risk), amber (intermediate risk) and red (high risk). A child with any red feature is treated as high risk. A child with amber features and no red feature is treated as intermediate risk. A child is low risk only when no amber or red features are present. The system is used with clinical what the person describes, examination, observations and appropriate investigations. It is not a home diagnostic score and does not determine the cause of fever. Green features do not guarantee harmless illness Green features include normal colour, normal response to social cues and comfortable breathing. The child may smile, wake easily and have moist mucous membranes. These findings reduce immediate concern when no amber or red features are present. They do not guarantee that the child will remain well. Parents and carers still need safety netting and advice about deterioration. The child should be reassessed if the pattern changes. Amber features require increased caution Amber features include a child who is less responsive than usual, wakes only with prolonged stimulation or has reduced activity. Other examples include pallor reported by a carer, dry mucous membranes, reduced urine or poor feeding in an infant. Increased breathing rate, nasal flaring and reduced oxygen saturation may also be amber features. Fever lasting five days or longer requires assessment. A temperature of 39°C or higher in a baby aged 3 to 6 months is also amber. One amber feature does not diagnose sepsis or another disease. It means the child requires clinical evaluation and an appropriate safety plan. Red features indicate high risk Red features include pale, mottled, ashen or blue colour. The child may fail to respond to social cues, appear very ill or remain difficult to wake. A weak, high pitched or continuous cry is concerning. Grunting, severe chest indrawing, very rapid breathing or reduced oxygen can indicate major respiratory compromise. Other red features include a non blanching rash, neck stiffness, a bulging fontanelle, focal seizures, status epilepticus, focal neurological signs, and fever of 38°C or higher under 3 months. A child with a red feature needs urgent medical assessment. Some red presentations require 999 and emergency transfer. The traffic light system does not replace judgement A parent may recognise that a child is behaving very differently before a numerical observation changes. Current NICE sepsis guidance treats parental or carer concern about altered behaviour as clinically important. Normal blood pressure does not exclude sepsis in a child. Pulse oximeters can also give misleading readings if the probe is poorly positioned or circulation is reduced. Readings may overestimate oxygen saturation in people with darker skin, particularly near decision thresholds. Clinicians use measurements as part of a wider assessment. Sepsis is a clinical syndrome Sepsis occurs when the body's response to infection causes life threatening organ dysfunction. It cannot be diagnosed from fever alone. Potential features include altered behaviour, abnormal breathing, poor circulation, reduced urine and mottled or blue colour. A child may have sepsis without a non blanching rash. They may also have normal blood pressure early in the illness. The safest approach is to respond to the overall pattern and deterioration. Current NICE NG254 provides age specific criteria for clinicians assessing suspected sepsis in people under 16. Breathing is a priority Observe the child when calm if possible. Concerning signs include: Very fast breathing. Grunting. Nostril flaring. The skin pulling in beneath or between the ribs. Pauses in breathing. Inability to feed because of breathlessness. Blue or grey lips or tongue. Inability to speak or cry normally because of breathing difficulty. A blocked nose can make feeding noisy. It should not cause severe chest recession, blue colour or reduced responsiveness. Breathing effort can worsen before oxygen levels fall. Coughs and colds Most young children experience repeated viral upper respiratory infections. Symptoms may include a blocked or runny nose, cough, mild fever and reduced appetite. A cough helps clear mucus. The colour of nasal mucus does not reliably distinguish viral from bacterial infection. Antibiotics do not treat ordinary viral colds. The clinical priority is whether the child can breathe, drink and remain responsive. A persistent cough, recurrent breathing difficulty or poor growth requires further assessment. Bronchiolitis type illness Bronchiolitis usually affects babies and children younger than 2. It often begins with a runny nose and cough. Breathing may become faster or more effortful over the following days. Feeding can decrease because babies struggle to coordinate sucking, swallowing and breathing. Most cases improve with supportive care. Some babies need oxygen, feeding support or hospital observation. Prematurity, very young age and heart, lung or immune conditions increase the risk of severe illness. The diagnosis requires clinical assessment and should not be made from wheeze or cough alone. Wheeze and noisy breathing Parents may use the word wheeze for several different sounds. True wheeze is usually a musical sound from narrowed lower airways. Stertor is a low snoring sound from the nose or throat. Stridor is a harsh upper airway sound, often louder during breathing in. The sound alone does not determine severity or cause. Stridor at rest, drooling with breathing difficulty or rapidly worsening airway symptoms require emergency assessment. Croup type symptoms Croup commonly causes a barking cough and hoarse voice. A harsh breathing in sound may occur when the child is upset. Stridor while resting is more concerning. Severe chest recession, drooling, exhaustion, blue colour or reduced responsiveness requires emergency help. A child should not have their throat examined forcefully at home when serious upper airway obstruction is possible. Fever with cough Fever and cough can occur with viral infection, bronchiolitis, pneumonia or other conditions. Rapid breathing, chest recession, grunting, persistent fever or reduced oxygen increases concern. A child may have pneumonia without complaining of chest pain. Abdominal pain can occasionally occur with lower chest infection. Clinicians interpret age adjusted breathing rate, work of breathing and examination together. Vomiting has several possible causes Vomiting commonly occurs with gastroenteritis. It can also occur with urinary infection, meningitis, appendicitis, bowel obstruction, raised pressure within the skull or metabolic illness. The colour and pattern matter. Green vomit can indicate intestinal obstruction and requires emergency assessment. Blood stained vomit, severe abdominal swelling or persistent focal pain also requires urgent review. Projectile vomiting in a young infant needs assessment, particularly when feeding and weight are affected. Diarrhoea and gastroenteritis Gastroenteritis commonly causes diarrhoea with or without vomiting. Most cases in young children are viral. The main immediate risk is dehydration. Blood or mucus in stool, severe abdominal pain, green vomit or a very unwell appearance may indicate another diagnosis. Diarrhoea lasting longer than expected also needs review. Antidiarrhoeal medicines are not routinely suitable for young children. Dehydration is a pattern Dehydration means that fluid loss exceeds fluid replacement. No single home sign proves or excludes it. Concerning changes include drinking much less, repeated vomiting, fewer wet nappies or less urine, dry mouth, reduced tears, sunken eyes, increasing sleepiness or irritability, cool hands and feet, and worsening overall appearance. A sunken fontanelle can occur in a dehydrated infant but is not reliable alone. The direction of change matters. A child who is steadily drinking less and passing less urine needs reassessment before severe signs develop. Children at increased dehydration risk Babies younger than 1 year have less fluid reserve. Risk is greater in babies younger than 6 months. Children with low birth weight may also dehydrate more quickly. Frequent watery stools, repeated vomiting and inability to drink increase risk. Malnutrition and significant underlying illness can reduce resilience. Lower thresholds for assessment are appropriate in these groups. Oral rehydration solution Oral rehydration solution, or ORS, contains water, salts and glucose in proportions that support intestinal absorption. It is more suitable than plain water for treating clinical dehydration from gastroenteritis. Small, frequent amounts may be easier to tolerate than a large drink. Breastfeeding should usually continue. A healthcare professional may provide a specific rehydration plan. A child with shock, severe deterioration or inability to tolerate ORS needs urgent medical treatment. Urine provides useful information Reduced urine can indicate dehydration or poor circulation. A dry nappy for much longer than usual should be considered with feeding and behaviour. Dark urine alone is not a complete measure of dehydration. Painful urination, urgency, new wetting or foul smelling urine may occur with a urinary infection. Babies may present only with fever, vomiting, poor feeding or irritability. A urine sample may be needed when no obvious source of fever is found. Ear symptoms Ear pain can occur with middle ear infection, external ear infection, throat infection or referred pain. Young children may rub an ear when tired or teething. Ear pulling alone does not diagnose infection. Most uncomplicated middle ear infections improve without antibiotics. Discharge, swelling behind the ear, a protruding ear or a very unwell child needs prompt assessment. Hearing difficulty persisting after the acute illness should also be reviewed. Sore throat Viral infections cause many sore throats. Bacterial tonsillitis is one possible cause. White patches do not establish the organism. The child's breathing, swallowing and hydration are more important than throat appearance alone. Drooling, inability to swallow, neck swelling, stridor or a muffled voice with severe illness requires urgent assessment. Antibiotic decisions should follow clinical assessment rather than one symptom. Rashes Rashes are common during viral illnesses. Their appearance can change with skin tone, temperature and lighting. A rash that fades temporarily when pressed is described as blanching. A non blanching rash does not fade under pressure. A non blanching rash in a child who appears unwell can indicate meningococcal disease or another serious condition. Do not wait for a rash when other signs suggest serious illness. Meningitis and sepsis can occur without one. The glass test has limitations Pressing a clear glass against a rash may help identify whether spots blanch. It cannot determine the cause. Very early meningococcal rashes may be difficult to see. Rashes may also be harder to recognise on darker skin. Check paler areas such as the palms, soles, inside the eyelids and mouth where appropriate. A seriously unwell child requires urgent help even when the rash blanches or is absent. Febrile seizures A febrile seizure can occur in some young children during a fever. The child may stiffen, jerk and become unresponsive. Most simple febrile seizures stop within a few minutes and do not cause brain damage. The first seizure still needs urgent medical assessment. Call 999 when it is the first seizure, the seizure lasts five minutes or longer, breathing is difficult, only one side is affected, seizures repeat without recovery, or the child remains unusually unresponsive. Do not restrain the child or place anything in their mouth. Place them somewhere safe and note the time. Antipyretic medicines treat distress Paracetamol or ibuprofen may be used for a feverish child who appears distressed. They are not required solely to reduce the number on the thermometer. They do not reliably prevent febrile seizures. The correct product and dose depend on age, weight and clinical circumstances. Do not give paracetamol and ibuprofen simultaneously unless specifically advised. Ibuprofen may be unsuitable during dehydration, chickenpox or some medical conditions. A fall in temperature after medicine does not exclude serious illness. Cooling methods A feverish child should not be over wrapped or deliberately made cold. Tepid sponging is not recommended for treating fever. Offer fluids and use comfortable clothing. The room should not be excessively hot. Shivering can increase discomfort. Treatment should focus on the child's comfort and clinical condition. Feeding during illness Appetite often falls during acute illness. Fluids are usually the immediate priority. Breastfeeding can continue and may be offered more frequently. Small, familiar foods can be offered when the child wants them. Force feeding is unnecessary. A baby who cannot feed because of breathlessness, repeated vomiting or reduced alertness needs urgent assessment. Supported home care Home care may be appropriate when the child has no red or amber features, is breathing comfortably, remains responsive, drinks adequately, continues passing urine, has reliable supervision, and has access to further care if symptoms change. Carers should receive clear safety netting. This includes which changes matter, whom to contact and how soon reassessment is needed. Home care is not a decision to ignore future deterioration. Parents and carers provide diagnostic information A parent knows the child's usual behaviour, feeding and movement. Statements such as "this is not how my child normally behaves" are clinically relevant. Professional assessment should not dismiss concern because one measurement appears normal. Likewise, carers should be told why a clinician is reassured and what would change that judgement. Good safety netting is a shared plan, not a warning to worry about everything.

The safest response to childhood illness depends on age, overall condition and change over time, not the symptom label alone.