What causes atopic allergy

The number of people with food allergies has risen sharply over the past few decades and, although the reason is unclear, other allergic conditions such as atopic dermatitis own also increased.

One theory behind the rise is that a typical child’s diet has changed considerably over the final 30 to 40 years.

Another theory is that children are increasingly growing up in «germ-free» environments.

This means their immune systems may not get sufficient early exposure to the germs needed to develop properly. This is known as the hygiene hypothesis.

Food additives

It’s rare for someone to have an allergic reaction to food additives. However, certain additives may cause a flare-up of symptoms in people with pre-existing conditions.


Sulphur dioxide (E) and other sulphites (from numbers E to E) are used as preservatives in a wide range of foods, especially soft drinks, sausages, burgers, and dried fruits and vegetables.

Sulphur dioxide is produced naturally when wine and beer are made, and is sometimes added to wine.

Anyone who has asthma or allergic rhinitis may react to inhaling sulphur dioxide.

A few people with asthma own had an attack after drinking acidic drinks containing sulphites, but this isn’t thought to be extremely common.

Food labelling rules require pre-packed food sold in the UK, and the relax of the European Union, to show clearly on the label if it contains sulphur dioxide or sulphites at levels above 10mg per kg or per litre.


Benzoic acid (E) and other benzoates (E to E, E and E) are used as food preservatives to prevent yeasts and moulds growing, most commonly in soft drinks.

They happen naturally in fruit and honey.

Benzoates could make the symptoms of asthma and eczema worse in children who already own these conditions.

Sheet final reviewed: 15 April
Next review due: 15 April

en españolEccema

How Is Eczema Diagnosed?

There is no specific test used to diagnose eczema. The doctor will glance at the rash and enquire about symptoms, the child’s past health, and the family’s health. If family members own any atopic conditions, that’s an significant clue.

The doctor will law out other conditions that can cause skin inflammation, and might recommend that your kid see a dermatologist or an allergist.

The doctor may enquire you to ban some foods (such as eggs, milk, soy, or nuts) from your child’s diet, switch detergents or soaps, or make other changes for a time to see if your kid is reacting to something.

When Should I Call the Doctor?

Children and teens with eczema are prone to skin infections.

Call your doctor correct away if you notice any early signs of skin infection, such as

  1. redness and warmth on or around affected areas
  2. pus-filled bumps on or around affected areas
  3. fever
  4. areas on the skin that glance love freezing sores or fever blisters

Also call your doctor if you notice a sudden change or worsening of the eczema, or if it isn’t responding to the doctor’s recommendations.

How Is Eczema Treated?

There is no cure for eczema. But treatments can assist with symptoms. The doctor will recommend diverse treatments based on how severe the symptoms are, the child’s age, and where the rash is.

Some are «topical» and applied to the skin. Others are taken by mouth.

Topical moisturizers. Skin should be moisturized often (ideally, two or three times a day).

What causes atopic allergy

The best time to apply moisturizer is after a bath or shower, with the skin patted dry gently. Ointments (such as petroleum jelly) and creams are best because they contain a lot of oil. Lotions own too much water to be helpful.

Topical corticosteroids, also called cortisone or steroid creams or ointments. These ease skin inflammation. (These aren’t the same as steroids used by some athletes.) It’s significant not to use a topical steroid prescribed for someone else. These creams and ointments vary in strength, and using the incorrect strength in sensitive areas can damage the skin, especially in infants.

Other topical anti-inflammatory medicines. These include medicines that change the way the skin’s immune system reacts.

Medicine taken by mouth. These can include antihistamines (anti-allergy medicine) to assist itchy kids sleep better at night, antibiotics if a rash gets infected by bacteria, and corticosteroid pills or other medicines that suppress the immune system.

Other types of treatment can include:

  1. wet wraps: damp cloths placed on irritated areas of skin
  2. phototherapy: treatment with ultraviolet light
  3. bleach baths: bathing in extremely diluted bleach solution

How Can Parents Help?

Help prevent or treat eczema by keeping your child’s skin from getting dry or itchy and avoiding triggers that cause flare-ups.

Attempt these suggestions:

  1. Kids should avoid becoming overheated, which can lead to flare-ups.
  2. Get rid of known allergens in your household and assist your kid avoid others, love pollen, mold, and tobacco smoke.
  3. Keep your child’s fingernails short to prevent skin damage from scratching. Attempt having your kid wear comfortable, light gloves to bed if scratching at night is a problem.
  4. Kids should drink plenty of water, which adds moisture to the skin.
  5. Kids should wear soft clothes that «breathe,» such as those made from cotton.

    Wool or polyester may be too harsh or irritating.

  6. Kids should take short baths or showers in warm (not hot) water. Use mild unscented soaps or non-soap cleansers and pat the skin dry before putting on cream or ointment. Teens should use unscented makeup and oil-free facial moisturizers.
  7. Ask your doctor if it’s OK to use oatmeal soaking products in the bath to assist control itching.
  8. Stress can make eczema worse. Assist your kid discover ways to deal with stress (like exercise, deep breathing, or talking to a counselor).

What Causes Eczema?

Doctors don’t know exactly what causes eczema. It might be that there’s a difference in the way a person’s immune system reacts to things.

Skin allergies may be involved in some forms of eczema.

What Is Eczema?

Eczema is a condition where the skin gets irritated, red, dry, bumpy, and itchy. There are several types of eczema, but the most common is atopic dermatitis. To numerous people, «eczema» and «atopic dermatitis» mean the same thing.

Who Gets Eczema?

Many kids and teens with eczema own family members who own it. Experts ponder it passes from parents to kids throughgenes. Eczema is fairly common.

People with eczema also may own asthma and some types of allergies, such as hay fever.

Eczema, asthma, and hay fever are known as «atopic» conditions. These affect people who are overly sensitive to allergens in the environment. For some, food allergies may bring these on or make them worse. For others, allergies to animal dander, dust, pollen or other things might be the triggers.

Eczema is not contagious.

What Are the Signs & Symptoms of Eczema?

The signs of eczema (EK-zeh-ma):

  1. include redness, scales, and bumps that can leak fluid and then crust over
  2. tend to come and go. When they get worse, it is called a flare-up.
  3. are mainly dry, itchy skin. Because it is so itchy, it is often called «the itch that rashes.»
  4. may be more noticeable at night

Symptoms can vary:

  1. Infants younger than 1 year ancient generally own the eczema rash on their cheeks, forehead, or scalp.

    It may spread to the knees, elbows, and trunk (but not generally the diaper area).

  2. Older kids and teensusually get the rash in the bends of the elbows, behind the knees, on the neck, or on the inner wrists and ankles. Their skin is often scalier and drier than when the eczema first began. It also can be thicker, darker, or scarred from every the scratching (called lichenification).

What Else Should I Know?

For numerous kids, eczema begins to improve by the age of 5 or 6. Sometimes it goes away. In other kids, it may start again as they enter puberty. Some people still own eczema as adults, with areas of itching that glance dry and scaly.

What is allergy?

Allergy is an immunological hypersensitivity mediated by immunoglobulin E antibody (IgE).

It is not a disease itself, but a mechanism leading to diseases such as rhinoconjunctivitis, urticaria, asthma and anaphylaxis. A normally harmless substance — love pollen, food or cat saliva — will cause the immune system to defend the body against it. In an allergic reaction the mast cells release a chemical called histamine, which is the primary cause for the allergic symptoms.

Allergies can be seen in numerous organs, but most commonly they affect the skin and mucous membranes, as these are the barriers between the body and the exterior environment.

Pollen allergy causes itching in the eyes and a runny nose. Contact allergies can induce a rash.

What causes atopic allergy

Food allergies cause itching in the mouth as well as abdominal pain and vomiting. The most severe allergic reaction is anaphylaxis. It can rapidly lead to a life-threatening condition where blood pressure drops and breathing may be obstructed because of throat swelling.

Allergy often starts at an early age. In most cases it persists through the life, but the symptoms may decrease, and some people outgrow their allergy entirely.

Sometimes other reactions are incorrectly referred to as allergy. For example, irritating or toxic substances can cause symptoms in the skin or abdomen that resemble an allergic reaction. Occasionally, sensitivity to certain foods, such as lactose intolerance, is also being called allergy.

However, only the immune-mediated hypersensitivity is true allergy.

Allergy starts with a sensitization phase that doesn’t yet cause allergic symptoms, but wires the immune system to recognize the allergen. The actual allergic reaction is launched upon the next encounter of the allergen and every time after that.


There is no known single cause for atopicdermatitis (eczema) and it probably represents more than one condition.

There are numerous theories regarding the underlying mechanisms. Current research is investigating the roles of the immune system,skin structural genemutations, defects in the skin cells (keratinocytes), the skin surface microbiome (bacteria, viruses and yeasts), and numerous other factors.

Current theories identify that atopic dermatitis is primarily a disease of the immune system, with cytokines being critical components to the disease. These cytokines, particularly IL-4 and IL (Th2 pathway cytokines) and IL (the Th22 axis cytokine) cause barrier defects and inflammation that result in the clinical features of eczema.

Atopic dermatitis

Most Common Allergies

Drug Allergy

Prescription drugs own been through a rigorous process of testing to ensure safety, despite this, a minority of individuals will develop side-effects.

Side- effects are termed “adverse drug reactions” by doctors and although the majority of adverse drug reactions are relatively minor and may even permit continuation with the drug, in some cases more severe symptoms can more


Rhinitis means inflammation of the lining of the nose Rhinitis is defined clinically as symptoms of runny nose itching, sneezing and nasal blockage (congestion).. Common causes of rhinitis are allergies which may be seasonal (‘hayfever’) or happen all-year-round (examples include allergy to home dust mite, cats, dogs and moulds).Infections which may be acute or chronic represent another common cause.

Rhinitis (whether due to allergic or other causes) is a risk factor for the development of asthma. Rhinitis is also implicated in otitis media with effusion and in sinusitis which should rightly be termed rhinosinusitis since sinus inflammation almost always involves the nasal passages as well. Read more

Food Allergy and Food Intolerance

If someone reacts to a food, they may own a Food Hypersensitivity (FHS).

FHS reactions involving the immune system are known as food allergy (FA), every other reactions are classified as food intolerances (FI).

What causes atopic allergy

Read more

Atopic Eczema (Dermatitis)

Eczema is a pattern of itchy skin rash consisting of tiny pink bumps that may join together producing ill-defined pink or red patches. There are numerous types of eczema – some own known causes. Dermatitis is the term used for eczema reactions that are caused by external agents/factors. Atopic eczema is often referred to as “infantile” of childhood eczema because that is when it generally develops. Atopic eczema is generally associated with allergies (hayfever or asthma) in either the affected individuals or in their shut relatives. Read more


What is asthma?
Asthma is a condition that causes swelling and inflammation inside the airways of the lungs.

This inflammation and swelling is there to a greater or lesser degree every the time in people with more inflammation there is the harder it becomes to breathe. People with asthma also own over-sensitive airways, so their airways react to triggers that do not affect other people. When sufferers come into contact with something that irritates their airways (a trigger), it can cause their airways to narrow. Read more

Allergy in Children

The bulk of allergic disease occurs in childhood, with asthma, allergic rhinitis, and eczema and food allergy comprising a significant percentage of the workload of doctors dealing with children in primary care and hospital paediatric departments.

In a recent large UK survey, 20% of children were reported to own had asthma in the previous year, 18% had allergic rhino conjunctivitis (hay fever) and 16% had eczema. This represents a massive increase in prevalence compared with similar studies in the s where prevalence rates were 3 fold lower.

What causes atopic allergy

Of these children 47% had at least two co-existing conditions e.g. asthma and eczema.

What causes atopic allergy

Read more

Skin Allergy

The allergic process can affect the skin producing 2 main types of rashes namely urticaria (hives, nettlerash, welts) or eczema (see atopic dermatitis section).

Urticaria is a red itchy bumpy rash that is often short-lived and can appear in various shapes and sizes anywhere on the is extremely common affecting 1 in 5 of the population at sometime in their some people urticaria is accompanied by large dramatic swellings commonly affecting lips, eyelids, tongue and hand called angioedema. Read more

A food allergy is caused by your immune system handling harmless proteins in certain foods as a threat.

It releases a number of chemicals, which trigger an allergic reaction.

Who’s at risk?

Exactly what causes the immune system to error harmless proteins as a threat is unclear but some things are thought to increase your risk of a food allergy.

Family history

If you own a parent, brother or sister with an allergic condition – such as asthma, eczema or a food allergy – you own a slightly higher risk of developing a food allergy. However, you may not develop the same food allergy as your family members.

Other allergic conditions

Children who have atopic dermatitis (eczema) in early life are more likely to develop a food allergy.

Non-IgE-mediated food allergy

There’s another type of food allergy known as a non-IgE-mediated food allergy, caused by diverse cells in the immune system.

This is much harder to diagnose as there’s no test to accurately confirm non-IgE-mediated food allergy.

This type of reaction is largely confined to the skin and digestive system, causing symptoms such as heartburn, indigestion and eczema.

In babies, a non-IgE-mediated food allergy can also cause diarrhoea and reflux, where stomach acid leaks up into the throat.


In children, the foods that most commonly cause an allergic reaction are:

  1. soya
  2. wheat
  3. milk – if a kid has an allergy to cows’ milk, they’re probably allergic to every types of milk, as well as infants’ and follow-on formula
  4. eggs
  5. peanuts

In adults, the foods that most commonly cause an allergic reaction are:

  1. tree nuts – such as walnuts, brazil nuts, almonds and pistachios
  2. fish
  3. peanuts
  4. shellfish – such as crab, lobster and prawns

However, any type of food can potentially cause an allergy.

What causes atopic allergy

Some people own allergic reactions to:

  1. sesame seeds
  2. pine nuts (a type of seed)
  3. fruit and vegetables – these generally only cause symptoms affecting the mouth, lips and throat (oral allergy syndrome)
  4. mustard
  5. gluten – a type of protein found in cereals
  6. celery or celeriac – this can sometimes cause anaphylactic shock
  7. meat – some people are allergic to just one type of meat, while others are allergic to a range of meats; a common symptom is skin irritation

The immune system

The immune system protects the body by producing specialised proteins called antibodies.

Antibodies identify potential threats to your body, such as bacteria and viruses.

They signal your immune system to release chemicals to kill the threat and prevent the spread of infection.

In the most common type of food allergy, an antibody known as immunoglobulin E (IgE) mistakenly targets a certain protein found in food as a threat. IgE can cause several chemicals to be released, the most significant being histamine.


Histamine causes most of the typical symptoms that happen during an allergic reaction. For example, histamine:

  1. affects nerves in the skin, causing itchiness
  2. causes little blood vessels to expand and the surrounding skin to become red and swell up
  3. increases the quantity of mucus produced in your nose lining, which causes itching and a burning sensation

In most food allergies, the release of histamine is limited to certain parts of the body, such as your mouth, throat or skin.

In anaphylaxis, the immune system goes into overdrive and releases large amounts of histamine and numerous other chemicals into your blood.

This causes the wide range of symptoms associated with anaphylaxis.