Allergies in children (Part one)

The number of children in the UK that have allergies has significantly grown. Senior consultant paediatrician Dr Basheer Peer-Mohamed has created an informative and thorough guide for parents looking to inform themselves about types, causes and symptoms.

Diagnosis and treatment are also covered in this two-part article. Read part two, here.

What causes allergy?

An allergic reaction is caused by our immune system going into overdrive when it comes into contact with harmless foods and other substances. The immune system treats these substances as threats to the body and releases lots of chemicals including something called histamine which causes swelling, itching, skin rash and other changes in the body that happen with a reaction.

An allergic reaction can be triggered by eating, breathing in or even by just touching the offending substance. Although we know what causes an allergic reaction, we do not fully understand why some people are allergic to certain things while others are not. 

What are the common allergies that you see in children?

There are certain foods that are well known in the allergy clinic and these include cow's milk and eggs. Nut allergy is fortunately a bit less frequent, but it still affects one in 40 children. Other allergies include fish, soya, latex, and insect stings, and there is a long list of other uncommon allergies.

In children with other related conditions such as eczema, hay fever and asthma, the risk of having a food allergy is even higher.

Inhalant or airborne allergies such as:

• Pollen
• Grass
• Weed
• House dust mites or from pets are another common cause for children presenting to the allergy clinic 

Are there different types of allergies?

Yes, there are two main types of allergies: the well-known immediate type allergy which is otherwise called IgE mediated and the delayed type or non-IgE mediated allergy. The immediate-type allergy is far more easily recognisable as it usually occurs within minutes of eating the food that the child is allergic to.

There is another type of allergy which is also increasingly recognised, and this is called Oral Food Pollen syndrome and children with this condition become unwell when eating certain raw fruits such as tomatoes, apples, kiwi, peaches and certain nuts.

There is also a very rare type of skin allergy called chronic urticaria which can cause recurrent or persistent skin reactions in response to food or environmental allergies. In infants, there is a unique type of allergy called Cow's milk protein allergy or intolerance which is not seen in older children or adults.

What kind of symptoms do you see with allergy?

The symptoms vary a lot depending upon the type of allergy the child has. With the immediate or IgE mediated type, a raised red skin rash called hives or nettles would appear in the face, usually starting from around the mouth and this rash can sometime spread rapidly to other areas of the body.

This can be accompanied by other symptoms such as:

• Intense itching
• Runny nose or sneezing
• Vomiting
• Abdominal pain

Occasionally there could be swelling of the lips, eyes and the child would appear pale with flushed facial skin. Very rarely, the allergy could lead to anaphylaxis which is an extremely severe and life-threatening reaction with difficulty in breathing and poor circulation affecting the blood pressure.

With the non-IgE mediated allergy, the symptoms can be delayed by several days and therefore it can be difficult to recognise or associate it with a specific food or environmental allergen.

The symptoms can be non-specific, such as:

• Worsening of pre-existing dry skin or eczema
• Abdominal pain
• Diarrhoea or constipation
• Gastro-oesophageal reflux and worsening of airway symptoms

Cow's milk protein allergy or intolerance that affects infants presents with a number of subtle and delayed symptoms such as:

• Reflux
• Irritability
• Constant crying
• Poor sleep
• Constipation
• Diarrhoea
• Poor weight gain
• Abdominal pain and bloating
• Passage of blood or phlegm in the stools

Looking for expert allergy advice? Visit Dr Basheer Peer-Mohamed’s Top Doctors profile to arrange an appointment.