- Introduction
- What exactly is a patch test?
- Who Should Consider a Patch Test?
- Understanding Irritation vs. Allergy
- What are the warning signs of an Allergy or Irritation?
- Correct Patch Test Procedure
- Common Irritating Ingredients
- How to Handle Symptoms After a Patch Test?
- Factors affecting the Result of the Patch test
- Types of Patch Tests
- Importance of Patch Testing In Skincare
- Final Words
Introduction
Patch Test? Have you ever been excited to try a new cosmetic and suddenly, upon applying it, wondered if your skin would be as excited as you because it felt like it was tickling and pricking? That’s exactly where the unsung but super-important hero comes in: The Patch Test!
Skincare product safety testing with patch tests confirms that the product will not irritate the skin under normal use conditions. Cosmetics that are non-irritating to consumers help build confidence in use and purchasing decisions, as well as create a reliable and safe image for your brand. Do you want to know more? stay with us.
What exactly is a patch test?
Patch test is a test for skin irritation and allergy by testing with standard substances from ready-made test strips on the skin to check for allergic reactions of the skin to certain substances. It is a tool with high sensitivity and specificity.
Patch tests are typically conducted on skincare products before they are introduced to the market to ensure they do not cause irritation or allergic reactions. Before launching products for children or adults with allergic skin, dermatological h-RIPT (Human Repeated Insult Patch Test) tests are also carried out to determine whether the tested product causes contact sensitization when used repeatedly.
Who Should Consider a Patch Test?
- Patients with various skin diseases whose symptoms worsen due to allergic contact dermatitis.
- People who have had dermatitis for a long time, especially on their hands, face, and around the eyes.
- Patients with chronic dermatitis who work in occupations with a high risk of allergic contact dermatitis, such as medical personnel, pharmacists, dentists, hairdressers, mechanics, and factory workers.
- People with an increased incidence of dermatitis.
However, the patch test cannot be tested in pregnant women, and the severity of allergic contact dermatitis symptoms varies from person to person. If it spreads and symptoms do not improve, you should see a doctor as soon as possible.
Understanding Irritation vs. Allergy
This is where the problem lies. Most of us don’t know the difference between an irritation and an allergy, so we define any unwanted reaction of our skin as an allergy. This, in turn, leads to negative opinions and to our loved ones being put off by these products. For this reason, sometimes it is worth entrusting our care to qualified people and taking advantage of a skincare consultation, which reduces the risk of choosing the wrong product.
Allergy
It is an inflammatory skin condition that occurs when the tolerance threshold for a particular ingredient is exceeded after direct contact with it. It activates our immune system and triggers allergies. Allergy is best detected by the epicutaneous test (patch test).
Skin Irritation
Also called contact dermatitis. Unlike allergies, it is not entirely related to our immune system. Skin irritation occurs when a certain substance irritates our skin, damaging the epidermal cells and disrupting their function. It also often disrupts the hydrolipid balance.
In addition, skin irritation occurs much faster than an allergy. A few/several hours are enough to notice the negative effects of using a certain product. Symptoms only appear at the site where the preparation was applied. They do not dissolve and often appear after the first contact with the substance.
What are the warning signs of an Allergy or Irritation?
The observation point indicated that the reactions could be redness, swelling, itching, or irritation, but there are more signs that you need to be aware of:
- Redness: Change in skin color to a redder hue. It may be the result of vasodilation (increased blood flow) due to inflammation, allergies, or irritation. This is an early sign of irritation.
- Swelling: Increase in volume in a body part due to fluid accumulation. In the context of a skin reaction, swelling may be caused by inflammation.
- Itching and stinging: An itchy or stinging sensation is a sign that the skin may not be tolerating the product, causing a desire to scratch or a sharp, brief pain like an insect bite.
- Burning: A sensation of heat or burning on the skin. It can be caused by irritants, allergies, or inflammation.
- Blisters or Rashes: Raised, fluid-filled lesions that can form on the skin due to friction, burns, irritation, or allergic reactions.
- Flaking or Dryness: Skin may become flaky or dry, indicating a negative response to the product.
- Urticaria: A skin rash characterized by raised, red bumps that may be itchy.
Correct Patch Test Procedure
- History: The appointed doctor will take your medical history to find the substance that is suspected of being the cause of the allergy or irritation.
- Avoid steroids: Stop taking steroids 2 weeks before the test to prevent inaccurate test results. Avoid sunbathing for 1 week before the test.
- Choose a small, sensitive area of your body: Choose a small, inconspicuous area of skin, such as the inside of your forearm or behind your ear, on the side of the neck, and bottom of your chin or jaw. The area behind your knees also works.
- Clean your skin: Make sure your skin is clean and dry before applying the product so that there are no errors in this test.
- Product application: Apply a small amount of the skincare products to the selected area (like a pea) and spread, leaving a layer of that product.
- Note/Repeat: Leave the product on your skin for the amount of time recommended in the product instructions. For example, if it is a cleanser, it should not be left on for more than 3 minutes. If it is a toner, serum, or cream, leave it on all day. During this period, watch for any signs of redness, swelling, itching, or irritation. If there are no results, repeat the test.
- Test result: If there are no adverse reactions after the recommended time (48 to 72 hours of product application), the product is likely safe for further use. If symptoms appear, avoid using it.
Common Irritating Ingredients
Some active ingredients in skincare can cause unwanted reactions. Here are some examples.
- Retinoids (retinal/retinol)
- Fruit acids (AHA, BHA, and PHA)
- Azelaic acid
- vitamin C
- Alcohols
- Fragrances
- Essential oils
- Volatile fragrances
- Strong detergents (SLS/SLES)
How to Handle Symptoms After a Patch Test?
- Clean the test site thoroughly: Gently washing the affected area with warm water and a mild cleanser helps remove the product and soothe the skin.
- Do not continue using the product: If you notice any signs of a reaction, do not continue using the product on a larger area of skin. This is especially important to prevent further irritation.
- Apply a cold compress: Applying a cold compress can help reduce swelling and soothe the skin. You can wrap a hydrogel bag in a thin towel and gently apply it to the affected area for 10-15 minutes.
- Use soothing products: Apply products containing aloe vera, chamomile, bisabolol, guaiazulene, or artemisia, known for their soothing properties.
- Avoid scratching: Although it may be tempting, avoid scratching the affected area, as this can worsen the irritation and increase the risk of infection.
- Consult a Health Professional: If symptoms persist or are severe, it is important to seek the guidance of a dermatologist who can diagnose you and prescribe the appropriate medications.
Factors affecting the Result of the Patch test
- Recent illnesses
- Medications taken
- Sun exposure
- Skin sensitivity
- Physical exertion
Types of Patch Tests
Open Patch Test
Tests for acute irritation or allergy to cosmetics. It is suitable for cosmetic formulas that are expected to be highly irritating. Most of the products used for testing are shower cream, soap, shampoo, hair curling solution, hair removal cream, etc. There are 2 tests:
- Single application open epicutaneous test
- Repeated application open epicutaneous test.
Single Application Open Epicutaneous Test
Apply the product to be tested without diluting it with water on the forearm or back, measuring 1 square centimeter. If irritation occurs, itching or redness will occur within 1-12 hours, while an allergy will occur within 48-72 hours.
Repeated Application Open Epicutaneous Test
also known as the use test, will be tested when there is no irritation or allergy in the single application open epicutaneous test to look for skin allergies and there are regular evaluations. Test by applying the product to the forearm, size 1 square centimeter, twice a day, morning and evening. Repeat for 3-14 days until redness appears. If there is no change in the skin, there is little chance of an allergy.
Closed Patch Test
Test for irritation and allergy using a test strip by placing the product to be tested on the test strip. Suitable for skincare formulas that appear to be safe for the skin. Multiple formulas can be compared in a single test. There are 2 tests:
- Single application closed patch epicutaneous test and
- Repeated application closed patch epicutaneous test.
Single Application Closed Patch Epicutaneous Test
Close the test patch on the back or upper arm. Read the results at 24, 48, or 96 hours as specified in the experimental protocol. Remove the patch and see if there is an allergic reaction. Observe redness.
Repeated application Closed Patch Epicutaneous Test
Close the test patch on the back or upper arm for 48 hours and read the results. Observe the changes in the skin after opening the test patch. Repeat for 14 days, possibly keeping the patch closed for 6 hours each day and reading the results, as specified in the experimental protocol. Because some substances may react slowly to the skin, it may take a long time for an allergic reaction to occur.
Importance of Patch Testing In Skincare
- Patch tests help identify specific ingredient allergies in skincare products, preventing potential reactions before you apply them to your face.
- It also helps us as consumers to follow the manufacturer’s instructions to maximize the safety and effectiveness of the product.
- For people with sensitive skin (whether due to skin sensitivity, illness, allergies, or inflammation), patch testing is crucial to avoid irritation and a possible negative result from skincare products.
- For people with weakened skin barriers, either due to diseases such as rosacea or acne where there is inflammation, or due to misuse of products, who are more susceptible to adverse reactions, the patch test becomes a fundamental tool to avoid irritations that could worsen the skin condition.
- The same applies to people who have a history of skin conditions such as eczema or dermatitis. They should pay special attention to patch testing and incorporate it into their routine since their skin needs additional care to avoid exacerbations of allergy or irritation symptoms.
- For people with already identified allergies, this test is an invaluable ally, as being able to identify any potential allergic reaction early prevents more serious consequences and contributes to a safer skincare experience.
- Some people may have allergies to specific ingredients common in Skincare products and this testing process helps detect these specific allergies before direct application to the face.
Final Words
A patch test is a great way to test out new skincare products. Not only does it help you determine if you are sensitive or allergic to a particular product, but it also helps you avoid unwanted irritation and breakouts. Not everyone reacts the same to certain ingredients or active ingredients in skincare products. What may be the best product for one person may cause undesirable reactions for another. But one thing you should consider, If you are afraid of introducing a new product into your skincare routine, consult a dermatologist.
