If you've ever developed a mysterious, itchy rash after trying a new skincare product, cleaning your house, or wearing a new smartwatch, you've likely experienced contact dermatitis. Affecting nearly 20% of the population, its triggers are hiding in places you'd never expect.

Unlike an immediate allergic reaction, contact dermatitis can take hours or even days to appear, making it incredibly tricky to identify the culprit. Here’s what you need to know about the most common offenders lurking in your cabinets and on your shelves.

1. The Reigning Champion: Nickel

Nickel is the most common contact allergen worldwide, and its sources are constantly evolving.

• Where you'll find it: Jewelry (even "hypoallergenic" kinds), belt buckles, eyeglass frames, zippers, smartphones, and smartwatches.

• Why it's a problem: It affects a staggering 18.2% of patch-tested patients. Women show dramatically higher sensitivity rates (17%) compared to men (3%). Sweat makes it worse by increasing the rate at which nickel leaches from metal objects onto your skin.

2. The Preservative Problem: Methylisothiazolinone (MIT)

This chemical has become the second most common contact allergen, with positive reactions jumping to 13.8% since it entered mass-market products in 2005.

• Where it hides: Shampoos, body washes, baby wipes, household cleaners, and even some paints.

• Why it's a problem: The EU banned it from leave-on cosmetics (like lotions) in 2017, but it's still permitted in rinse-off products and cleaning supplies at high concentrations.

3. The Invisible Threat: Fragrances

Fragrance allergies are uniquely deceptive. The ingredients might be harmless in a new bottle but can become potent allergens over time.

• Where they lurk: Perfumes, lotions, detergents, air fresheners, and even products labeled "unscented" (which often use masking fragrances).

• Why it's a problem: Common chemicals like linalool and limonene oxidize when they react with air, transforming into powerful allergens. Companies can also hide dozens of potential irritants under the single word "fragrance" or "parfum" on the label.

4. The Modern Tech Trigger: Acrylates

Once an issue mainly for dentists and nail technicians, acrylates are now a growing problem for everyday consumers thanks to wearable technology.

• Where you'll find them: Adhesives for fitness trackers and smartwatches, continuous glucose monitors, gel and acrylic nails, and some dental materials.

• Why it's a problem: These devices create 24/7 skin contact with medical-grade adhesives and plastics that can sensitize skin over time.

5. The Hair Dye Danger: PPD

Para-phenylenediamine (PPD) is a chemical used in permanent hair dyes that is notorious for causing severe reactions, including facial swelling and blistering.

• Where you'll find it: Permanent and semi-permanent hair dyes, especially dark shades.

• Why it's a problem: A PPD allergy often leads to cross-reactivity, meaning you may also react to certain sunscreens, local anesthetics, and even black temporary tattoos.

6. The "Natural" Myth

Don't assume that a "natural" or "plant-based" label means a product is safe for sensitive skin. Some of the most potent allergens come from nature.

• Common culprits: Tea tree oil, lavender oil, propolis (bee glue), and colophony (pine resin).

• Why it's a problem: These botanical extracts can be more allergenic than their synthetic counterparts. "Plant-based" does not equal "hypoallergenic."

7. The Pandemic Effect: Household Chemicals

The COVID-19 era brought professional-strength chemicals into our homes, creating new sensitization patterns.

• Where you'll find them: Hand sanitizers (benzalkonium chloride), disinfecting wipes (industrial preservatives), and mask materials (rubber accelerators).

• Why it's a problem: Constant exposure to these powerful chemicals has sensitized people who previously had no issues.

How to Get Answers and Protect Your Skin

If you're experiencing unexplained rashes, patch testing by a dermatologist is the gold standard for identifying your specific triggers. Remember, you can suddenly react to a product you’ve used safely for years.

But reading every ingredient list for dozens of potential allergens is overwhelming and impractical.

Your best defence for this is the pom app. It not only identifies thousands of common allergens but also lets you build a personalized profile of your own specific triggers. Shop with confidence, knowing exactly what's right for your skin.