Don’t take our word for it. Here’s every fact on this site, with its evidence grade, its caveats, and a link to the source, so you can check us.
We start you on the strong ones: findings that have been replicated or come from one large, well-controlled study. Moderate and weak facts are here too, labeled for what they are. Use “Link to this fact” to share a single card.
Skin allergy / Measured in people or real products
Most patients who reacted to oxidized scent chemicals (58%) also had other fragrance allergies or a history of reacting to fragranced products.
Weak evidence: 31 positive patients.
Skin allergy / Other evidence
Across three chemical-intolerance case studies with symptom improvement tied to reduced VOC exposure, blood IgE allergy panels for 16 common indoor/outdoor/food antigens did not track or explain the symptom changes, and only 2 of the full 37-patient cohort (5.4%) had elevated antibodies to both dust mite and cockroach allergens.
Weak evidence.
Caveats
Uncontrolled case-series observation; absence of IgE elevation does not rule out other allergic or non-IgE immune mechanisms, and the paper does not test a specific non-allergic mechanism directly.
Source: Rincón et al. 2024, Primary Health Care Research & Development Link to this fact
Skin allergy / Review of other studies
Fragrance causes both irritant and allergic contact dermatitis, among other adverse skin reactions, and fragrances are the most frequent chemicals causing contact dermatitis overall.
Weak evidence.
Caveats
Narrative review statement, not a ranked prevalence study; does not establish that contact dermatitis (from any cause) is the single most common adverse reaction to skincare products in general, only that fragrance is a leading cause of contact dermatitis specifically and that it can be either irritant or allergic.
Source: Pastor-Nieto 2021, Current Treatment Options in Allergy Link to this fact
Skin allergy / Review of other studies
Fragrance chemicals are also used as food flavorings, and dermatologists consider systemic contact dermatitis from fragrance-related food flavorings in fragrance-allergic patients whose eczema does not clear after 6 weeks of full topical fragrance avoidance.
Weak evidence: Clinical management guidance from a narrative review, not a measured ingestion-exposure or prevalence study; does not quantify how often food flavorings are the actual culprit.
Skin allergy / Other evidence
The National Eczema Association's Seal of Acceptance certification criteria exclude chemical UV-absorber sunscreens, accepting only physical (mineral) sunscreens containing titanium, zinc, or iron oxide.
Weak evidence.
Caveats
This reflects one certification body's precautionary ingredient-exclusion criteria for eczema-prone skin, not measured comparative allergic-contact-dermatitis incidence rates between mineral and chemical UV filters — no such comparative rate data were found in our evidence base or in this pass. Do not read this as evidence that mineral filters cause fewer ACD reactions in the general population, only that this eczema-focused body's rules treat them as the safer default.
Source: National Eczema Association 2026 Link to this fact
Skin allergy / Other evidence
Hairdressers who wore gloves during dye application did not have significantly lower hand loads of hair-dye chemicals than those who did not, but the gloves were often re-used for months, put on after mixing, or turned inside out, and glove users did the more hand-intensive whole-head jobs.
Weak evidence: Glove use was confounded with task and technique; 3 vs 1 hairdressers had PPD; not a test of properly used single-use gloves.
Source: Lind et al. 2005, The Annals of Occupational Hygiene Link to this fact
Skin allergy / Other evidence
Acetophenone azine, a chemical found in foam (EVA) shin guards, shoe insoles, and flip-flops, has caused allergic skin reactions in a small number of young athletes in Europe and Canada.
Weak evidence: Roughly a dozen documented patients, all from case literature; no prevalence data; the column is a society award announcement.
Information, not medical advice. See also: myths we won’t tell you.