Dr Haroon Ahmad
Eczema Patch Testing: Your Ultimate Guide to Understanding Allergy Tests and Common Irritants in Eczema..
Uncover triggers of eczema flare-ups and learn about the significance of patch testing.
What We'll Cover - Eczema Patch Testing.
Key Takeaways
Eczema flare-ups are triggered by allergens and irritants which can be identified through allergy tests.
Personal, environmental, irritant, and food triggers are commonly responsible for eczema flare-ups.
Allergy tests like Skin Prick, Blood Tests, and Patch Tests are effective in identifying triggers.
Proton Health app aids in tracking personal and environmental triggers.
Patch testing, offering a high success rate, is the gold standard in allergy testing.
Introduction - Patch Testing and Eczema
For many people with eczema, certain substances, including certain allergens and irritants, can trigger a flare-up. This is where allergy testing can be extremely helpful, by tracking down these irritants, we're better positioned to avoid and prevent our flare-ups.
In this comprehensive guide, we'll explore the different types of allergy tests, how these irritants cause flare-ups and delve deeper into patch testing.
Understanding Allergies and Hypersensitivity Responses in Eczema
Allergies arise when your immune system, the body's usual protector, responds excessively to certain substances called allergens. These allergens could be in our environment, in the food we eat, or hidden in the products we use daily. For people with eczema, the immune system is especially sensitive, reacting more than it should.
This overreaction can make eczema symptoms worse and trigger flare-ups. This heightened immune response is known as a 'type 2 hypersensitivity response'. In such cases, your immune system mistakenly creates chemicals called IgE antibodies to fight substances that are normally harmless.
This type 2 hypersensitivity response often kicks in 48 to 72 hours after contact with the allergen. The resulting symptoms can range from mild itching and inflammation to severe allergic reactions. This delay in reaction can make it a bit tricky to identify what's causing the flare-ups, underlining the importance of allergy tests to discover them.
A Breakdown Of Common Eczema Triggers
The following list covers a comprehensive set of triggers that cause eczema flare-ups. They can be broadly broken down into Personal, Environmental, Irritants and Food triggers. Here they are in more detail:
1. Personal Factors:
Sleep: Lack of sleep or irregular sleep patterns can weaken the immune system and exacerbate eczema symptoms.
Stress: Stress can cause a hormonal imbalance and immune system response that may trigger flare-ups.
Hormonal Changes: Fluctuations in hormone levels, such as during menstrual cycles or pregnancy, can impact eczema.
Illness: Common colds, the flu, or infections can stimulate an immune response leading to a flare-up.
2. Environmental Factors:
Weather: Dry, cold air can make the skin more prone to dryness and itching. Conversely, hot, humid weather can lead to sweating and irritation, triggering a flare-up.
Allergens: Environmental allergens such as dust mites, pollen, mould, and pet dander can trigger eczema in some people.
Hard Water: High mineral content in water can dry out the skin and exacerbate eczema.
3. Irritants:
Soap and Detergents: Harsh soaps, shampoos, and laundry detergents can strip away the skin's natural oils, causing dryness and irritation.
Clothing: Synthetic fabrics or wool can be irritating to the skin. Cotton clothing is generally better tolerated.
Fragrances and Dyes: Artificial fragrances and dyes in personal care products can be irritating to sensitive skin.
Sweat and Saliva: In babies, drool can be a skin irritant. In adults and children, sweat can also cause irritation and lead to a flare-up.
In addition, there are several ingredients that are found in various products including skincare ingredients. You should be on the lookout for the following:
Fragrance: This is a broad term that can encompass thousands of individual ingredients, many of which can cause skin irritation or allergic reactions.
Sodium Lauryl Sulfate (SLS) and Sodium Laureth Sulfate (SLES): These are commonly used as foaming agents in soaps, shampoos, and body washes. They can strip the skin of its natural oils, leading to dryness and irritation.
Parabens (methylparaben, propylparaben, butylparaben, and ethylparaben): Used as preservatives in many skincare products, parabens can cause skin irritation in some people.
Formaldehyde and Formaldehyde-releasing Preservatives: These are used to prolong the shelf-life of skincare products. However, formaldehyde is a known allergen that can cause skin reactions.
Alcohol (denatured alcohol or isopropyl alcohol): Found in many skincare products, it can dry out the skin, leading to irritation and potential flare-ups.
Retinol and Retinoids: While these can have benefits for many skin types, they can also cause irritation and dryness, particularly for those with sensitive skin or eczema.
Essential Oils: Though natural, many essential oils can be irritating to the skin. Examples include citrus oils like bergamot or grapefruit, and others like peppermint.
Dyes: Artificial dyes can be a trigger for some people with eczema.
Propylene Glycol: It's used in a variety of skincare products to enhance product penetration, but can be irritating to the skin.
4. Foods:
Dairy: Dairy products, particularly cow's milk, can be a trigger for some people.
Eggs: Eggs are a common allergen and can trigger eczema in some people.
Gluten: Some individuals with eczema may have a sensitivity or intolerance to gluten.
Nuts and Seeds: Nuts and seeds are common allergens that can trigger eczema in some people.
Soy: Soy and soy products can be a trigger for some people.
It can be relatively straightforward to discover your Personal and Environmental triggers using the Proton Health app. However, when it comes to Irritants and Foods, there are simply too many out there to pinpoint your triggers. That's where allergy testing comes in…
Allergy Tests: Types, Procedures, and Pros & Cons
Here we delve into the various types of allergy tests available, examining how they are performed, what they look for, and their respective pros and cons.
Skin Prick Tests
The skin prick test, also known as puncture or scratch test, is a straightforward and quick procedure to identify allergies. It involves pricking the surface of the skin with a tiny, sterile needle that has been dipped in a solution containing a possible allergen. Then, the skin's response is observed for about 15 to 20 minutes.
Pros: This method provides rapid results, usually within 20 minutes, making it a convenient testing option. It is particularly effective for diagnosing food allergies, such as to peanuts, eggs, or shellfish, and respiratory allergies, like to dust mites, animal dander, or pollen.
Cons: Despite its advantages, skin prick testing has its limitations. It may not be reliable for diagnosing contact allergies associated with eczema. Additionally, it can be uncomfortable, especially for children, and there's a slight risk of triggering a severe allergic reaction.
Blood Tests (RAST or ELISA)
Radioallergosorbent (RAST) or enzyme-linked immunosorbent assay (ELISA) tests are blood tests that measure the level of specific IgE antibodies produced in response to suspected allergens. This is the same chemical that's produced by the immune system when it reacts to something you've come into contact with.
Pros: These tests are particularly useful when skin prick testing isn't feasible, such as in people with severe eczema or those who are taking certain medications like antihistamines. They also pose no risk of triggering an allergic reaction.
Cons: Blood tests tend to be more expensive than skin tests and results take longer to be ready, usually a few days to a week. Also, they may not be as sensitive as skin tests and could miss some allergies.
Patch Tests
Patch tests are important in diagnosing contact allergies that can worsen eczema. In this test, small amounts of potential allergens are applied on patches, which are then placed on the skin, usually the back. After 48 hours, the patches are removed and the skin is examined for reactions. A further reading is usually taken after another 24-48 hours.
Pros: Patch tests boast a high success rate, identifying relevant allergens in up to 70% of patients with suspected allergic contact dermatitis. They're excellent for detecting delayed allergic reactions and identifying allergens that cause contact dermatitis, a common problem for people with eczema.
Cons: Interpretation of patch test results requires expertise, as false-positive or false-negative results can occur. Some people may experience lingering skin irritation or other side effects. Also, not all potential allergens are included in standard test panels, which could potentially miss less common allergies.
Which Test Should You Use?
The preferred method of testing depends on your individual circumstances and the nature of your symptoms. A healthcare professional will be able to guide you on the most appropriate test. Here's a rough guide on which one should be used when:
Skin prick tests are typically preferred for diagnosing food and respiratory allergies, due to their quick results and high sensitivity for these types of allergens.
Blood tests are preferred in certain situations where skin testing is not feasible or practical. This includes patients with severe eczema, those taking medications that interfere with skin tests, or those who might be at risk for a severe allergic reaction.
Patch tests are preferred for identifying contact allergens — substances that cause reactions when they come into contact with the skin, which is particularly important for individuals with eczema.
Patch Testing - The Gold Standard
Patch Testing is becoming more common due to the large amount of potential irritants in products that we come across each day. It also boasts a higher success rate compared to other means of allergy testing and is quickly becoming the gold standard. The following is what to expect if you opt for a patch test:
Initial Consultation
The process starts with an initial consultation with a dermatologist or allergy specialist. They will review your medical history, examine your skin, and discuss your symptoms. The goal is to identify potential allergens that might be contributing to your skin problems.
Patch Application
Next, the patch testing begins. Your healthcare provider will apply small amounts of potential allergens on patches. These patches are then placed on your skin, usually on your back. The number of patches used can vary, but typically between 20 and 30 are used, each containing a different potential allergen.
Waiting For A Reaction
After the patches are applied, they are left in place for 48 hours. During this time, it's crucial to keep the patches dry and avoid activities that cause heavy sweating.
Interpreting The Results
Once the patches are removed, your doctor will check your skin for reactions. This is usually done at least twice: once when the patches are initially removed (usually at 48 hours) and again a few days later (usually at 72-96 hours). This is because some reactions might take longer to show up.
Positive reactions will typically appear as small red, raised patches, similar to eczema. However, they can also look like hives or even blisters in severe cases. Your healthcare provider will interpret the results. They have the experience to distinguish true positive reactions from irritant or false reactions.
Post Test Recommendations
If you have positive reactions, your doctor will provide you with detailed information about the allergens that caused them. They will advise you on how to avoid these substances in your everyday life, which can often involve changes to your skincare routine, diet, or lifestyle.
Common Allergens Identified in Patch Tests
Chemical Allergens
Apart from the commonly recognised allergens such as nickel, fragrances, preservatives, and hair dyes, there are several other chemical substances that can cause allergic contact dermatitis. These include:
Rubber Accelerators: These are chemicals used in the production of rubber products, including gloves, shoes, and elastic bands. They can cause skin reactions in sensitive individuals.
Epoxy Resins: Epoxy resins are used in a variety of products, from plastics and adhesives to paints and coatings. Contact with these substances can lead to skin reactions.
Paraphenylenediamine (PPD): This is a chemical substance used in hair dyes, textiles, fur dyes, dark-colored cosmetics, and temporary tattoos, which can cause allergic reactions.
Isothiazolinones: These are biocides used in a wide range of personal care products and can cause allergic contact dermatitis in sensitive individuals.
Food Allergens
While food allergies are typically identified through ingestion, some food-related substances can cause contact dermatitis. These can include:
Balsam of Peru: Balsam of Peru is a fragrant resinous liquid used in perfumes and flavorings. It's often used as a marker for fragrance allergy. This substance is naturally occurring in a variety of foods such as spices, citrus, tomatoes, and certain alcoholic beverages.
Cinnamal and Cinnamates: These are common in foods like cinnamon and are also used in fragrances. They can cause reactions in some individuals.
Gluten: While typically associated with celiac disease, some individuals may have skin reactions to gluten. This would be more commonly associated with a condition known as dermatitis herpetiformis.
Environmental Irritants
Several environmental irritants can cause contact dermatitis:
Plants: Poison ivy, poison oak, and poison sumac are the most common plant allergens causing contact dermatitis. Other plants like chrysanthemums, sunflowers, daffodils, and tulips can also cause skin reactions in sensitive individuals.
Sunscreens: Certain chemicals in sunscreens, such as oxybenzone, avobenzone, and octocrylene, can cause allergic reactions.
Metals: In addition to nickel, other metals such as gold, cobalt, and chromium can cause allergic reactions.
Extended Panel for Patch Testing
Beyond the standard list of allergens, there are several more substances that you might consider for patch testing if standard testing doesn't provide answers. Here is an extensive list:
Ethylenediamine
Neomycin
Tetracaine
Benzoyl Peroxide
Cinnamic Aldehyde
Ethylene Oxide
Yellow Dye No. 5 (Tartrazine)
Wool Alcohols
Dimethylol Dimethyl Hydantoin
Cocamidopropyl Betaine
Thimerosal
Octyl Gallate
Dodecyl Gallate
Propyl Gallate
Euxyl K400
Methyldibromo Glutaronitrile
2-Bromo-2-Nitropropane-1,3-Diol
Dibromodicyanobutane
Bronopol
Glutaral
Quaternium-15
Methenamine
Formaldehyde-Releasing Preservatives
Primin
Oak Moss
Balsam of Peru
Eugenol
Isoeugenol
Farnesol
Cinnamic Alcohol
Cinnamic Aldehyde
Hydroxycitronellal
Geraniol
Citral
Citronellol
Amyl Cinnamaldehyde
Nickel(II)sulfate hexahydrate
Peru balsam
Colophonium
Diazolidinyl Urea
p-Phenylenediamine (PPD)
2-Mercaptobenzothiazole (MBT)
Formaldehyde
Potassium dichromate
Lanolin Alcohol
Epoxy resin, Bisphenol A
Hydroperoxides of Linalool
Citral
Cobalt(II)chloride hexahydrate
Imidazolidinyl Urea
Paraben mix
Thiuram mix
Mercapto mix
Fragrance mix I
Black rubber mix
Methylisothiazolinone + Methylchloroisothiazolinone
Cocamidopropyl Betaine
Sesquiterpene lactone mix
Fragrance mix II
Toluene-2,5-Diamine
Toluene-2,5-Diamine Sulfate
Quaternium-15
Tixocortol-21-pivalate
Benzocaine
Budesonide
Propylene Glycol
Benzyl Alcohol
Tea Tree Oil oxidized
Isoeugenol
Compositae mix II
p-Chloro-m-Cresol
Propolis
Chloroacetamide
Methylprednisolone aceponate
Mixed dialkyl thiourea
Cocamide DEA
DMDM Hydantoin
Carba mix
Hydroperoxides of Limonene
Benzophenone-3
Geraniol
Benzalkonium Chloride
Hydroxyisohexyl 3-Cyclohexene Carboxaldehyde
Textile dye mix
Amerchol L-101
Ammonium Persulfate
Benzoic Acid
Sodium Benzoate
Chloroxylenol (PCMX)
2-Bromo-2-Nitropropane-1,3-Diol
Betamethasone-17-Valerate
2-Hydroxyethyl methacrylate
Sodium Metabisulfite
Lidocaine
Iodopropynyl Butylcarbamate
Methylisothiazolinone
Remember, understanding your personal triggers is the first step towards managing your eczema effectively. Always consult with your doctor or a dermatologist if you think you might have allergies contributing to your skin condition.
Discovering Your Triggers With Proton Health
Unmasking the hidden triggers of eczema has never been easier with the Proton Health app, your Personal Skin Health Coach. Our unique digital assistant is not just a passive tool for logging symptoms and possible causes—it's an active participant in your skincare journey, aiding in the identification and management of your individual eczema triggers.
The Proton Health app enhances your understanding of eczema triggers by integrating your personal experiences with our scientifically validated database. It not only identifies potential triggers through your personal journal entries, but also empowers you with customised insights and advice. This enables you to address your unique triggers effectively and take control of your eczema management.
Harnessing the collective wisdom of evidence-based research, personalised data, and user-friendly technology, the Proton Health app transforms your journey towards better skin health into a seamless, interactive experience. Discover your triggers, learn how to address them, and take control of your skin health journey today with Proton Health. Try out the app here now.
Conclusion
Patch testing is really helpful if you're dealing with eczema. It can help figure out what's causing your flare-ups, so you can begin to avoid these irritants. If you suspect that certain things in your environment are causing flare-ups, patch testing could provide powerful answers. But remember, always talk to your doctor or skin specialist before you go for any kind of allergy test.
