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Allergies and Eczema – Is there a link?

Allergies & Eczema

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Both allergies and Eczema are 2 conditions that are commonly seen in society. Often we see that these two conditions coexist, but is there actually a link between the two or is it only a coincidence?

What is an allergy?

An allergy occurs when your immune system reacts to a foreign substance. This substance may be pollen, animal dander, bee venom, or even a food item. Allergies don’t occur in everyone. What is allergic to you may not be allergic to your friend.

Our immune system produces substances called antibodies. They are there for our protection. However, when you have an allergy, your immune system produces antibodies that identify a particular substance as harmful, although it really isn’t most of the time. Therefore, if you come in contact with such an allergen, your immune system can cause a reaction that can occur as inflammation in your skin, airways, sinuses, or digestive system.

The severity of an allergy can vary from person to person. It may range from a minor irritation to anaphylaxis which is potentially life-threatening and considered an emergency. Most allergies are not curable, however, your symptoms can be relieved with various treatments.

What are the symptoms of allergies?

The symptoms depend on the allergen, which is the substance involved, and where the exposure occurs in your body. For example, hay fever, which is also known as allergic rhinitis can cause sneezing, itchy nose, and eyes, runny or stuffy nose with watery or red eyes.

Skin can get affected in allergies such as for certain foods. Hives or urticaria is a common occurrence. They are red, itchy welts that result from skin reaction. Depending on the severity, your lips, eyes, face, or throat can get swollen. This is known as angioedema. An insect sting allergy can give a large area of edema (swelling) at the site of the sting as well as hives and itching throughout your body.

What is Eczema?

Eczema is also known as Atopic dermatitis. It is a chronic skin condition commonly seen in children. It is a long term condition which usually has several flares and remissions. It can also be an allergic skin condition that causes your skin to redden, itch, flake, or peel. Atopic dermatitis is quite common which affects around 20% of children.

Eczema can be either wet or dry. These lesions are almost always itchy. Scratching can increase the risk of infection as germs get in through damaged skin. Continuous scratching can cause lesions to become thick, discolored, and leathery.

Eczema can run in families because it is an atopic condition which has an inheriting tendency. It can also associate with Hay fever (Allergic rhinitis), allergic conjunctivitis, or bronchial asthma. Usually, there is a family history of one or more of these conditions suffered by a family member or a close relative.

There is an entity called contact dermatitis which is quite similar to eczema. It is a skin reaction to something that it comes in contact with. These are irritants such as poison ivy, soap, bleach, certain metals, fabric dyes, hair dyes, and other irritants. Here, a red rash appears with an itching, burning, or stinging sensation in the area which was exposed or got contacted. Sometimes blistering (fluid-filled vesicles) and oozing can occur. Patch testing is done to identify contact allergens.

Impaired skin barrier in atopic dermatitis facilitates the penetration of potential allergens. Therefore children with atopic dermatitis have a possibility of contact allergies leading to contact dermatitis. They may have unacknowledged contact allergies contributing to skin symptoms. Here, patch testing is an important tool for screening children with atopic dermatitis which helps in their further management too.

Children with atopic dermatitis are also at a greater risk of sensitization to certain allergens like metals, metal products, and some skincare products.

Seborrheic dermatitis is another type of skin condition which commonly affects areas with hair growth or areas where oil (sebum) is secreted. It may be caused by a reaction to yeast which is a natural commensal (part of normal flora) on our skin. Here, the rash is dry and scaly and sometimes appears red. Seborrheic dermatitis may be similar to eczematous lesions.

What are the similarities between urticarial skin allergy and eczema?

Both eczema and allergies involve the immune system. Therefore, eczema and allergies are closely related.

  • Both conditions can cause severe itching
  • Redness of skin
  • Scratching can give rise to swelling of the area (edema)
  • It can occur in any place of your skin

What are the differences between skin allergy and eczema?

Eczema can be oozing or dry, but urticarial skin reaction or hives doesn’t ooze. Eczema can get infected but hives do not usually get infected.

Is eczema actually an allergy?

Most eczema types are not allergies. Eczema cannot be caused by an allergy. However, we have seen that eczema flare-ups occur following exposure to certain allergens in susceptible individuals. For example, certain foods can cause an allergic reaction which may give rise to an eczema flare-up.

Studies have found that eczema and food allergies are closely related. Certain foods can lead to allergic reactions and eczema flare-ups. These common food allergens are milk, eggs, wheat, soybean, nuts, and meat items. These foods can commonly affect kids and worsen their eczema symptoms. It may not be so in adults.

Ex: Babies with atopic dermatitis are found to have a higher risk of developing food allergies.

What is Atopy?

Atopy refers to a genetic tendency to develop allergic diseases like asthma, atopic dermatitis (eczema), allergic rhinitis (hay fever), and allergic conjunctivitis. Atopy is associated with heightened immune responses to common allergens such as food allergens or inhaled allergens.

Atopy runs in families. Therefore, you may have seen a mother with asthma having a baby with hay fever or atopic dermatitis or vice-versa. Research is still being carried out to study the link between these atopic conditions.

What is ‘Atopic march’?

According to allergy experts, atopic dermatitis is an early step of ‘Atopic March’. There is a common clinical progression from atopic dermatitis to food allergies and sometimes to respiratory allergies and allergic asthma in some children.

This biological process occurs because allergens reach your immune cells easily through the dysfunctional skin barrier that is affected by atopic dermatitis.

The link between eczema and allergies is still unclear and the connection is complicated. Scientists are still learning new details regarding this link.

Some areas of study include;

  1. Genes – A gene has been identified which causes a lack of a protein type called Filaggrin in their skin. Filaggrin protects the outer layer of our skin and keeps the germs out. When Filaggrin is lacking our skin barrier becomes weak, making it vulnerable to irritants, such as chemicals, soap, and detergents. Germs and allergens too can easily get in. Therefore, people with a lack of the Filaggrin gene are more sensitive to allergens like pollen, pet dander, and certain food items. A defect in the filaggrin gene by a mutation increases the risk of eczema.
  2. Body’s reaction to allergens – Research has found that eczematous skin has a defective skin barrier. There are small gaps that dries out your skin as well as let allergens and germs enter your body.

What happens when germs and allergens enter our skin?

Our skin sees these allergens as foreign substances and causes a reaction. It is called inflammation, where our body makes chemicals that can lead to swelling and redness. The prompting to make these chemicals within your body is done by the allergens. Therefore, if you suffer from eczema or if you are susceptible to it, you may have an outbreak or a flare-up, if you get exposed to an allergen.

  1. Antibodies – It is identified that the antibody IgE (Immunoglobulin E) plays a role in our body’s allergic response. If you are a person with eczema, you may have a higher level of IgE antibodies in your bloodstream. It is not yet understood why people with eczema have too much IgE in them and the exact role of it towards eczema.

Learning about these links between allergies and eczema will help you to control your eczema flare-ups in a better way.

How can you avoid allergens to prevent flare-ups of eczema?

These allergens are known as trigger factors because they initiate the reaction to cause the flare-up of your eczema.

  1. Avoid allergy triggers – Identify the triggers which worsen your eczema or leads to a flare-up in well-controlled disease. Different people may have different triggers. However, in some, it will be difficult to find an exact trigger factor.

preventing eczema flares

Once you identify them, it is easier to avoid getting exposed.

Sometimes these triggers can be unavoidable, such as pollen during spring and summer seasons. But allergens like pet dander, mold, dust mites, and allergic food items can be avoided if you are careful.

Some tips to avoid allergy triggers….

  • Use dust-proof pillow covers and mattresses
  • Avoid animals and pets especially furry dogs and cats
  • Remove carpets
  • Mop floors
  • Stay indoors when pollen counts are high
  1. Avoid skin irritants –Your skin can get irritated by soaps, detergents, wool, perfume, chemicals, and even cigarette smoke. Avoid them as much as possible once you correctly identify that these are common irritants that can lead to your eczema flare-up.
  2. Maintain an eczema journal –Remember when, where, and what you were doing when your eczema flared up. Write them down in a journal. If you go through it carefully, you may figure out what your triggers are. You can share this journal with your doctor, so that he or she can see the pattern and advice you accordingly, during your appointments.

Link Between food allergies and eczema

It is a well-known fact that food allergy and eczema are highly associated. However, all eczema patients do not have food allergies. Research has found that 20-40% of children with moderate to severe eczema have an IgE mediated food allergy.

Can food allergies exacerbate eczema?

There are some studies which suggest that people with positive allergy testing to egg can get better if they eliminate egg from their diet. Testing for food allergies can be beneficial in children with severe eczema who do not improve with optimized skincare. Testing for food allergies can be done through skin testing or blood tests to identify the specific IgE antibody for the allergen.

Although a positive result means that the allergic antibody is present, it doesn’t necessarily mean that you will have an allergic reaction.

Research has found that food allergies and eczema co-exist, but we still do not know for sure whether food allergies worsen eczema. Further research needs to be done to confirm this fact.

According to another study, food allergy was found among 50.7% of patients with atopic dermatitis.

Ex: eggs, milk, wheat, soy

Scientists have found that children with both atopic dermatitis and food allergy have structural and molecular differences in the top layers of healthy-looking skin near the eczema lesions, although children with atopic dermatitis alone do not have these differences. However, the outer appearance of the eczema rash doesn’t show any difference between the 2 groups. According to published research defining these differences can help to identify children who are at a higher risk for developing food allergies.

Therefore, it is helpful to identify food allergies in order to improve symptoms in patients with atopic dermatitis.

The link between inhaled allergens and eczema

It is identified that airborne triggers (allergies in the air) act as inhalant allergens and are highly associated with eczema.

Ex: Pollen, dust mite, animal dander

Therefore, there is a strong association between eczema and respiratory allergies such as asthma and allergic rhinitis.

According to studies, atopic dermatitis is characterized by skin barrier defects (such as mutations in the Filaggrin gene and other alterations of immune cells). These factors promote the development of food allergies and asthma too.

Scientists have tried to introduce potential food allergens to at-risk infants to prevent food allergies. But does this prevent the babies from eczema? Research data is inadequate to come to a conclusion.

References:

  • https://pubmed.ncbi.nlm.nih.gov/29750772/
  • https://pubmed.ncbi.nlm.nih.gov/29222945/
  • https://pubmed.ncbi.nlm.nih.gov/23610604/
  • https://www.nih.gov/news-events/news-releases/scientists-identify-unique-subtype-eczema-linked-food-allergy
  • https://link.springer.com/article/10.1007/s13671-015-0121-6
  • https://nationaleczema.org/atopic-dermatitis-and-allergies-connection/
  • https://www.longdom.org/scholarly/eczema-journals-articles-ppts-list-3188.html
  • https://www.mayoclinic.org/diseases-conditions/atopic-dermatitis-eczema/symptoms-causes/syc-20353273
  • https://www.mayoclinic.org/diseases-conditions/allergies/symptoms-causes/syc-20351497
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