Introduction Filaggrin, a structural protein of the uppermost skin layer, stratum corneum (SC) plays an important role in aetiology of contact dermatitis (CD). Filaggrin contributes to the mechanical strength of the skin while its degradation products are major constituent of natural moisturising factors (NMF) responsible for adequate skin hydration. The major determinant of NMF in the skin are mutations in the filaggrin gene, a known risk factor for occupational contact dermatitis. Next, NMF can be affected by dermal exposure to skin irritants or contact allergens. The levels of NMF might therefore serve as a biomarker of individual susceptibility or to assess skin damaging effect of irritants and allergens.

Methods In experimental studies in humans, the levels of NMF components in the SC were determined before and after exposure to common skin irritants (SLS; n-propanol, acetic acid and NaOH) and contact allergens (Cr, Ni, MCI/MI and PPD).

Results All skin irritants led to significant decrease in NMF levels in the SC while among contact allergens this effect was observed only by MCI/MI.

Discussion Decrease in NMF levels indicates damage of the skin barrier which occurred after dermal exposure to both, contact allergens and irritants. Therefore, NMF might be a useful biomarker to detect early effects associated with dermal exposure to chemicals in occupational settings. Furthermore, NMF might be useful to identify skin damaging properties of contact allergens.