TL;DR
AllerNote is a freemium allergen-aware ingredient scanner with a custom profile, active conflict checker, and cross-reactor mapping across 900-plus allergens. Use it if you’ve had a real patch test and need to translate the dermatologist’s allergen list into shopping behavior. Skip it if you’re guessing your sensitivities; it works best with documented results.
The problem AllerNote actually solves is the awkward gap between a patch test and your next shopping trip. A North American 80-panel test will hand you a printout of fifteen confirmed reactions you barely recognized in the office. Two weeks later, you’re standing in front of a moisturizer aisle, and that printout is in a drawer at home. AllerNote is the bridge.
What AllerNote is and isn’t
It’s a personal allergen profile plus an ingredient scanner. You enter your confirmed reactions (fragrance mix I, methylisothiazolinone, nickel, parabens, whatever your printout says). The app maps cross-reactors. You scan a product. You get Safe, Warning, or Avoid in three seconds.
It is not a diagnostic tool. It doesn’t decide what you’re allergic to. The cross-reactor mapping is conservative, which means it will sometimes flag things you’d personally tolerate. That’s the right error to bias toward.
Who it’s for
This is for someone who has seen a dermatologist, gone through a real patch test (TRUE Test, North American 80-Comprehensive, or a customized panel), and now has a printout of confirmed sensitizers. It’s also useful for parents of kids with confirmed contact allergies and for adults managing chronic eczema or contact dermatitis. If you’ve never been formally tested and you just “think you’re sensitive,” the tool will work but it’s not built for guessing. Start with a derm visit, then come back.
The features that matter
Custom allergen profiles are the core. You’re not picking from a generic “avoid fragrance” preset; you’re inputting your actual reactions. Methylisothiazolinone is different from methylchloroisothiazolinone, and AllerNote treats them as different. The granularity matches what a real test report gives you.
The active ingredient conflict checker is the secondary feature, and it’s underrated. It tells you when two products in your routine create a problem; for example, AHA paired with retinoid same-night on a barrier that’s already been flagged. This isn’t allergen logic, it’s irritant-load logic, and it’s the thing most ingredient apps ignore.
Cross-reactor mapping across 900-plus allergens is the depth. If you’re allergic to one corticosteroid, the others in its group may also flag. If your test showed Balsam of Peru sensitivity, the app warns you about the long list of cousins that share its allergenic compounds. That mapping is genuinely valuable and tedious to do by hand.
What mainstream beauty media miss about allergen tools
Beauty media tends to talk about “sensitive skin” as a single category. Real contact allergy is not the same as a stinging response to vitamin C. It’s a delayed Type IV hypersensitivity reaction with specific molecular triggers. The press almost never separates these. AllerNote does, and that’s the contrarian position. The slow-skincare answer to “my skin reacts to everything” is rarely “buy the gentler thing.” It’s “find out what you’re actually reacting to, then build around the answer.”
Where it falls short: the cross-reactor mapping leans cautious, sometimes too cautious. I had three products flag yellow for a peripheral cousin compound I’ve used for years without issue. The app is correct to err on the side of warning, but a confidence score would be useful.
Real-world test
I imported a confirmed eight-allergen profile (mine includes a couple of fragrance components and one preservative). Over 19 days I scanned every new product I considered buying and every product currently on my shelf. The app correctly flagged a leave-in conditioner I’d been using as a Warning because of an aroma chemical I’d tested positive to. It correctly cleared the moisturizer I rely on most. It produced one false alarm on a serum where the offending ingredient was in dilution well below threshold. Net: it saved me roughly $90 of return shipping and one weekend of compromised skin.
Pair this with a strict approach to patch testing every new product before face application. Eczema readers may also want to revisit our sensitive-skin routine, and there’s a useful overlap with postpartum sensitivity, when hormonal shifts can unmask reactions that weren’t there before.
How it stacks against EWG Skin Deep
EWG Skin Deep is the household name. It’s also a generalist tool that treats every ingredient as if it were dangerous until proven otherwise, and it’s not built around your specific allergens. AllerNote is the opposite philosophy: nothing is universally dangerous, but the things on your list are dangerous for you. That framing is more honest and more useful for anyone with diagnosed sensitivities.
For pure curiosity or “is this brand sketchy,” EWG is fine. For “can I use this without losing a week to a flare,” AllerNote wins.
Browse the rest of our sensitive-skin coverage on Elelaf.
Try it here: AllerNote.
FAQ
Do I need a patch test to use it? No, but the tool is much better when you do. The profile depends on real data.
Does it cover hair care and household products? Limited. Skincare is the strongest category at launch.
Is the cross-reactor mapping accurate? Mostly yes, with cautious bias. Expect occasional yellow flags that are technically correct but practically minor.
Is the freemium tier sufficient? Yes for most readers. Paid unlocks deeper conflict analytics and broader product database access.
What if my allergen isn’t listed? You can submit it. The 900-plus list is growing.
Sources: DeKoven JG et al., Dermatitis (2019) on North American Contact Dermatitis Group patch test results; American Academy of Dermatology on managing contact dermatitis.