Is annoying eczema caused by sensitive skin or skin allergies?
In the outpatient clinic, we frequently see patients with eczema, and doctors suspect it may be caused by a certain cosmetic product.allergyAt this time, patients often ask, "I used it a few days ago and nothing happened, how could it be the culprit for this allergic reaction?" or they come to the clinic with facial eczema and ask, "Doctor, do I have sensitive skin?"
"Skin allergy" and "Sensitive skinThese are two different concepts, but they overlap and influence each other at certain levels, which can cause confusion. In fact, once you understand them, you will know how to avoid and treat them.
Sensitive skin is prone to contact dermatitis; everyday products may be the culprits.
Sensitive skin refers to a skin condition that is easily triggered by internal and external factors (emotions, stress, diet, sun exposure), resulting in dryness, redness, or peeling. Congenital sensitive skin includes atopic dermatitis and rosacea; acquired sensitive skin is related to improper skin care, such as incorrect face washing methods, lack of sun protection and moisturizing, or changes in age.
Skin allergies refer to inflammatory reactions caused by skin contact with specific allergens or irritants. For example, contact with strong acids/alkalis or long-term contact with detergents can cause "irritant" contact dermatitis; or repeated exposure to chemicals, fragrances, preservatives, metals, etc. can cause "allergic" contact dermatitis, which can manifest as redness, swelling, itching, peeling, and other inflammatory reactions similar to eczema.
However, people with "sensitive skin" are indeed more prone to irritation and "contact dermatitis" than people with normal skin.
Many allergens in daily life are common culprits in causing allergic contact dermatitis, such as nickel, latex, Peruvian fragrances, and paraphenylenediamine. Common culprits include:
1. Nickel: It is the most common allergen and is often found in earrings, necklaces, watches and belt buckles. When nickel in these accessories causes an allergy, dermatitis will appear on the earlobe, back of the neck, wrist and around the navel. Therefore, doctors can use the location of eczema to determine the accessories and allergens that may be causing the allergy.
2. Latex: Some people experience skin inflammation and blisters upon contact with latex gloves or latex products. They may even experience immediate allergic reactions from inhaling latex proteins suspended in the air. The structure of latex proteins is similar to certain components of fruits such as bananas, avocados, kiwis, chestnuts, and peaches. Therefore, people allergic to latex are also prone to allergic reactions after eating these fruits, a condition known as Latex-fruit syndrome.
3. Peruvian fragrance: It is a complex resin containing a variety of compounds. It smells like vanilla and cinnamon and is often used in perfumes, skincare products or food as a flavoring agent. Tomatoes, spices (vanilla, cinnamon, cardamom, cloves), and citrus fruits also contain components of Peruvian fragrance. Therefore, people who are allergic to Peruvian fragrance should also pay attention to allergic reactions when consuming the above foods.
4. p-Phenylenediamine (PPD): A common ingredient in hair dyes. The darker the color of the hair dye, the higher its PPD content may be. It can easily cause dermatitis on the hairline, ears, back of the neck, and even eyelids.
Where is the skin problem? The location can help identify potential allergens.
In addition to analyzing the components, we can also infer possible allergens from the location where allergic dermatitis occurs:
1. Scalp: Common scalp allergens come from hair dyes, perms, or shampoos. However, because the scalp is relatively thick and has strong resistance, allergic dermatitis often appears at the hairline, around the ears, on the back of the neck, or on the eyelids (when the hair flows onto the face while rinsing).
2. Eyelids: Allergic to ingredients in mascara, eyeliner, eyeshadow, and nail polish (fingers touching the eyelids after applying nail polish).
3. Lips: Lip balm, lipstick, lip gloss, nail polish, toothpaste, dental floss, mouthwash, fragrance.
4. Neck: Jewelry, perfume, nail polish.
5. Underarms: Deodorant, antiperspirant.
When our bodies first come into contact with an allergen causing allergic contact dermatitis, our immune cells are activated and develop a memory of that allergen. However, this doesn't immediately trigger an allergic reaction; this process is called sensitization, which takes about 10 to 14 days. Only when we are exposed to the same allergen again will our bodies react, producing symptoms of dermatitis such as redness, swelling, peeling, and itching.
This is similar to how, after a house is burgled for the first time, you become more vigilant. When the burglar breaks in a second time, because of your previous experience and preparation, you react quickly and apprehend the burglar. Therefore, just because you used a certain cosmetic product without problems before doesn't mean it wasn't the culprit that caused this contact dermatitis!
If you suspect you have contact dermatitis, stop using the suspected product to avoid further exposure to the allergen, and consult a dermatologist as soon as possible for treatment. Doctors can also use a patch test (note) to help diagnose the product causing the allergy, allowing patients to clarify the situation quickly.
Note: In a patch test, various suspected allergens are dropped onto small patches and applied to the back to observe the skin's reaction, thereby identifying the culprit causing the allergy.
