Methods: New employees at The Jackson Laboratory enrolled in a cohort study underwent skin prick testing (SPT) at baseline and every six months to mouse and a panel of aeroallergens (net wheal ≥3mm=+SPT). Mouse allergen exposure was measured every six months using personal air monitors. Eczema was defined as self-reported doctor-diagnosed eczema. Cox proportional hazard modeling was used to examine the association between baseline eczema and incident mouse skin test sensitivity and adjust for potential confounders.
Results: Participants (n=394) were followed for a median of 24 months. Fifty-four percent were female, 89% were white, and 64% handled mice. At baseline, 7% reported doctor-diagnosed eczema and 9% current asthma; 61% had at least one positive skin test. At 30 months, 36% of those with eczema vs. 14% of those without eczema had developed a positive mouse skin test (log-rank test, p=0.02). After adjusting for age, race, sex, smoking status (current, former, never), current asthma, hay fever, number of positive skin tests at baseline, and mouse allergen exposure, doctor-diagnosed eczema was an independent risk factor for incident mouse skin test sensitization (HR [95% CI]= 5.6 [2.1-15.2], p=0.001).
Conclusions: Doctor-diagnosed eczema was a risk factor for incident mouse sensitization, independent of atopy and allergic respiratory disease, suggesting that a defect in skin barrier alone may increase the risk of skin sensitization.