The diagnosed incidence of cosmetics-related skin reactions in North America has increased by 2.7 times in North America over the decade between 1996 and 2006, finds a study recently published in the Journal of the American Academy of Dermatology. This study did not include irritant and allergic reactions to sunscreens.
In 1996-1998, out of people referred to patch testing, 22% of females and 17% of males had an irritant or allergic reaction to cosmetic ingredients. These numbers more than doubled in 10 years, when 49% of females and 49% of males tested had a positive patch reaction to cosmetic ingredients.
Other data from Europe confirms the trend A Danish study found that contact sensitization to cosmetic allergens doubled from 1990 to 1998. In a 2013 survey, European dermatologists noted a 5-year increase in males reporting sensitive facial skin.
The main driver behind the increase in irritant and allergic skin reaction, most likely, is the increase in the amount of cosmetic products and ingredients used in daily routines. This, for example, explains the lower incidence of skin reactions to cosmetics in men compared to women, as well as the recent increase in skin sensitivity for men that is linked with the explosion of marketing of cosmetics for men.
A 2004 study found that males used 6 personal care products per day on average with 85 ingredients while females used 12 products with 168 ingredients.
Larger availability of patch testing is probably also contributing to the increased number of confirmed positive reactions (more tests = more cases), but it is highly unlikely that this is the main factor.
The most common allergens for both sexes include preservatives methylisothiazolinone and methylchloroisothiazolinone, fragrance, formaldehyde-releasing preservatives (for example, quaternium-15, DMDM hydantoin, imidazolidinyl urea, diazolidinyl urea), as well as surfactants (cleansing ingredients) cocamidopropyl betaine and amidoamine. In females, hair dye ingredients (for example, paraphenylenediamine) were also found to be common allergens. Unfortunately, the study does not report which skincare ingredients were most likely to cause irritant skin reactions. This is most likely due to the fact that irritant reactions are harder to link to an individual ingredient and we have less robust techniques for identifying the sources of irritant reactions. For practical purposes, it is worth keeping in mind that overall there is a big overlap between common allergens and irritants in skincare (e.g. fragrance, surfactants), and it might make sense to avoid common allergens in cosmetics even if your skin sensitivity seems to be driven by irritant reactions.
Source: Contact Dermatitis to Personal Care Products is Increasing in Males and Females: North American Contact Dermatitis Group (NACDG) Data, 1996-2016 https://pubmed.ncbi.nlm.nih.gov/33039486/