More and more children, it seems, are being diagnosed with allergies.

An allergy means that your child’s immune system is triggered into an allergic reaction when it comes into contact with allergen – a substance that causes an allergic reaction.

Basically the immune system believes the substance, such as nuts, milk or pollen, as harmful and will produce antibodies to fight it.

This in turn causes your body to release chemicals, cause physical symptoms such as a runny nose, to rid the body of the harmful invader.

The good news is that most children tend to grow out of them as their immune system matures, the bad news is that while they have them, parents have to be extra cautious when it comes to managing them correctly and preventing flare ups.

Food allergies

According to healthcare provider Bupa food allergies are the most common form of childhood allergy.

Most common foods that cause allergies include peanuts, tree nuts (Brazils, almonds, cashews, hazelnuts, walnuts and pecans), fish and shellfish, cows’ milk, eggs, soya and wheat..

Hay fever

Hay fever is an allergy to pollen, pet fur or house dust, in children it doesn’t normally develop until they are about seven.

Sensitivity to chemicals

Younger children may get allergic reactions to certain everyday chemicals, such as certain washing powders. This normally takes the form of eczema.

How to recognise an allergy

These are some common reactions, according to Bupa.

• skin reactions (e.g swelling and itching, a rash around your mouth, eczema and flushing)
• wheezing or shortness of breath  – asthma
• diarrhoea, feeling sick, vomiting and bloating
• coughing
• a runny nose
• sore, red and itchy eyes
• itchy or swollen lips, mouth, tongue and throat

A peanut or nut allergy can be triggered just by being in the same room where the food has been.

The worse case scenario

You may have heard of an allergic reaction called anaphylaxis, or anaphylactic shock. This is rare but can be fatal.

The allergic reaction is so intense it can swelling of the airways and throat, making it difficult to breathe. If this happens the suffer can lose consciousness.

So what causes allergies?

There is lot of debate about how allergies start. Doctors believe that some food allergies start in the womb.

There is also some evidence that breastfeeding after eating certain foods, can trigger an allergy; although not in the case of peanuts.

Children with parents who have eczema or asthma, are also thought to be more likely to develop allergies themselves.

How to diagnose an allergy

Your GP will need to refer your child to an allergy clinic before a diagnosis can be made. At the clinic your child may be given  skin prick tests – when  extracts of the suspected allergens are put on a small patch of skin, usually the forearm or back, and a very small, fine scratch is made. If the skin turns red, an allergy to that substance can be diagnosed.

If a food allergy is suspected an ‘elimination and challenge diet’ – where you remove the suspected allergy food from your youngster’s diet. If symptoms get better then the food can be re-introduced to confirm an allergy. If a severe allergy is suspected, this will be done under medical supervision in hospital.

Blood tests. The RAST (radioallergosorbent) test measures levels of food-specific antibodies in your blood.

How do you treat an allergy?

If the allergen cannot be avoided, such as pollen, then you need to treat the symptoms, which can be controlled by using an antihistamine.

With skin sensitivity and food allergies, avoidance – if possible – is the best option.

Of course if your child has a severe food allergy, then they may be at risk of anaphylaxis and will need to take certain precautions, checking food packaging, letting other family members and other carers know.

Allergies: earn warning signs in children:

The following symptoms were published on the BBC online health site in 2007. but provide a useful guide to parents who think their child may have an allergy.

Allergic shiners

Allergic children and adults have typical darkening around the eyes called allergic shiners. This blue discoloration is caused by congested veins and looks like smudged mascara.

Dennie-Morgan lines

Young children with nasal and chest allergies have characteristic Dennie-Morgan lines. These are crease-like wrinkles that form under the lower eyelid folds.

Long face syndrome

Children with asthma and nasal allergies have so-called long face syndrome: a high-arched palate and protruding upper teeth. This develops after years of constant nasal blockage.

The nasal mucous membranes (turbinates) swell from irritation, so much so that the nasal passages become completely blocked. These children are forced to breathe through their mouths, which also affects tooth growth.

Nasal salute

Intense nasal itching leads to the ‘nasal salute’ – the child tends to rub their nose with the palm of the hand, usually in an upward direction. This constant rubbing leads to a crease or wrinkle across the bridge of the nose.

Facial tics

Children with nasal allergies tend to pull funny faces, as their noses are always itching. They may then go on to develop uncontrollable facial tics or twitches and constantly sniff, making strange noises.

Teachers often complain they’re being naughty and fooling around, when the real cause is an untreated nasal allergy.

Keratosis pilaris

Children with allergies, and potential eczema sufferers, have characteristic dryness and roughness of the skin, particularly on the cheeks, upper arms and chest. This dryness is called xerosis and usually has a sandpaper-like texture called keratosis pilaris, which reduces the skin barrier to irritants and infection.

Atopic eczema

Atopic eczema may develop as a consequence of dry skin, especially in the elbow and knee joints of children. Children with eczema constantly fidget and scratch, leading to a misdiagnosis of being hyperactive, when in fact it’s their itchy skin distracting them.

Conjunctivitis

With chronic eye allergies, the inner parts of the eyelids develop a swollen, cobblestone-like appearance from allergic conjunctivitis.

Children also tend to rub away the outer third of their eyebrows.

Glue ear

Children with nasal allergies may develop glue ear, when mucous becomes trapped behind the eardrum in the middle ear. This results in temporary deafness, discomfort and a poor attention span.

Postnasal drip

Children may experience a constant postnasal drip and repeated sore throats from allergic mucous building up and being discharged into the throat. Serious nasal allergies also reduce children’s senses of taste and smell.

Futher help and support:

Allergy UK has lots of help and support for parents .

The NHS website also has plenty of information if you think your child has an allergy.