Guides and field notes.

Contact dermatitis affects roughly 15–20% of the general population, and for those living with it, ingredient labels can feel like a foreign language. The scientific names are unfamiliar. The same allergen hides under a dozen synonyms. And even when you do identify your allergen — say, nickel, or methylisothiazolinone — a single diagnosis rarely captures the full picture. Most people with contact dermatitis react to allergens that belong to chemical families with known cross-reactivities: avoiding the diagnosed allergen but not its relatives leads to persistent flares that feel inexplicable.

The guides below are written for patients navigating that complexity. They draw on the clinical literature that underpins MySkinIQ's analysis engine — the North American Contact Dermatitis Group (NACDG) patch test series, European Society of Contact Dermatitis (ESCD) research, and published cross-reactivity studies — and translate it into plain language you can use.

MySkinIQ's reference data organizes active allergens into usable cross-reaction families. Understanding that approach makes you a better label reader — and makes the app's verdicts more meaningful.

• Contact dermatitis basicsHow ACD differs from ICD, the sensitization mechanism, and what to expect from symptoms
• Patch testingThe NACDG standard series, what each allergen tests for, and how to read your results
• Cross-reactivity scienceWhy allergens cluster into families and how to use that knowledge to build an avoidance strategy
• INCI ingredient namesHow to identify allergens on cosmetic labels using international nomenclature
• Fragrance allergensThe fragrance mixes, individual chemicals, and natural extracts most commonly implicated in reactions
• Preservative allergensFormaldehyde releasers, isothiazolinones, parabens, and the preservative families to watch