Children are often unwell as their immune systems are developing while they are exposed to new viruses all the time.
Babies, toddlers and school age children are prone to colds and stomach bugs.
Then there are the common childhood conditions and illnesses that may affect your child such as measles, slapped cheek syndrome and chicken pox - but how do you know when it is something more serious?
NHS consultant paediatrician Dr Ashley Reece says: “By and large, parents should trust their instincts.
“There are 10 ‘red flag’ symptoms that should signal a visit to the doctor or hospital, but if you’re in any doubt, always contact your doctor.”
Here are ten 'reg flag' symptoms every parents should know about
A temperature of more than 37.5C (99.5F) is a fever. But most GPs stress that the number on the thermometer isn’t as important as how children seem in themselves.
If they are still playing and eating normally there’s probably no need to worry, but if they seem irritable or unusually drowsy it is cause for concern. The exception is babies under three months with a high temperature, who should see a GP.
Most fevers in kids are caused by colds or other viral infections and can be treated at home using children’s paracetamol, such as Calpol.
Watch for an unexpected second rise in temperature a few days into a cold or virus, this can indicate a secondary ear or throat infection, which may require antibiotics.
If your child is wheezing or experiencing fast or laboured breathing, they will need immediate medical help.
Respiratory problems account for a third of emergency visits to paediatric wards and are the fifth most common cause of death in UK children between the age of one and 14.
The cause may be asthma, or a viral infection such as pneumonia, which is why breathing difficulties often follow cold symptoms such as fever, runny nose, cough or sore throat.
Respiratory distress, or an increase in effort of breathing, means your child isn’t getting enough oxygen and must go to casualty.
Other signs are:
A bluish color around their mouth, lips or fingernails
Pale or grey-looking skin tone
Nostrils flaring excessively
Skin 'sucking in' between, above, or below the rib cage
Severe tummy pain
Abdominal pains are common and are usually down to a tummy upset, change of food or constipation.
But severe pain lasting more than a few hours could mean appendicitis, especially if it is concentrated on the lower right side.
This sudden inflammation of the appendix can be life-threatening and missed in young children as they rarely get telltale signs that adults suffer, such as a fever, nausea or vomiting.
Get prolonged tummy pains checked.
Fever with a rash, stiff neck and a headache
These symptoms together, along with a dislike of bright lights, vomiting, difficulty waking, confusion or fits, can signal that your child has meningitis – a potentially life-threatening swelling of the membranes in the brain and spine.
It is important to note that sometimes not all the symptoms occur – for example, the neck stiffness or rash can be absent.
Lots of illnesses cause rashes, but the telltale one, which is a sign of septicemia or blood poisoning caused by meningitis, presents as spots or blotches, anywhere on the body, and they don’t lose redness when a glass is pressed against them.
When septicemia occurs with meningitis, it can cause leg pain, mottled skin and cold hands and feet.
If you notice any of these, go to hospital as early treatment is vital to prevent fatal complications. See meningitis.org for more advice.
Headaches, especially after a fall
Headaches are common but the ones to get checked out include:
Those following a blow to the head, as they may suggest concussion or brain injury, especially if your child has vomiting, vision changes, dizziness, confusion, sensitivity to light and/or noise, and changes in mood.
Those getting progressively worse, occurring first thing in the morning along with vomiting, or if vomiting relieves pain.
Doctors say parents often sense if a baby’s crying is excessive or doesn’t sound 'right'.
Generally, if it is constant, higher pitched than usual and there is fever, it could indicate a serious infection or even meningitis, so get help immediately.
Figures from Allergy UK show childhood allergies have risen dramatically in the last 20 years, with nearly half of kids being diagnosed with at least one by the age of 18.
Food allergies can prove fatal. Those most likely to cause allergies in kids are eggs, fish, nuts (particularly peanuts) soy, seafood and milk. Other potential serious allergens include bee stings and some medications.
Potential signs of a life-threatening allergic reaction that requires an immediate trip to casualty include:
Wheezing or difficulty breathing
A stinging nettle-like rash
Swelling of lips, throat or tongue
An unexplained faint – even if they seem fine in a minute – should be checked by your GP. If they don’t recover within a few seconds, have difficulty breathing, a weak pulse, and/or experiences body spasms or seizure, take them to hospital.
Frequent urination with weight loss, thirst and lethargy
These can be signs of Type 1 diabetes. It is vital to see a doctor as soon as possible as this can result in severe dehydration and coma.
Chronic diarrhoea and vomiting
Cases that last several hours can be a sign of a serious infection, and may result in dehydration – a potentially dangerous state, especially for young children and babies.
Oral rehydration drinks, such as Dioralyte, can help. Call your doctor for advice.
For more information visit the NHS choices website here.