Congenital ichthyosis is associated with increased risk of allergic disorders

The congenital ichthyoses are rare hereditary epidermal differentiation disorders characterized by severely impaired skin barrier function. Patients with atopic dermatitis and one form of congenital ichthyosis, Netherton syndrome, are known to be at increased risk of atopy, presumably linked to barrier impairment. However, an increased risk of atopy has not been assessed in individuals with other congenital ichthyoses despite their severe barrier impairment.

Our aim was to explore rates of atopy in patients with congenital ichthyoses versus in a control population.

This cross-sectional survey study enrolled patients and parents of children aged 6 to 11 years with a physician-confirmed diagnosis of congenital ichthyosis and self-reported ichthyosis subtype. Designation of having food allergy, allergic rhinitis, or allergic asthma required a physician's diagnosis and affirmative responses about signs and symptoms. The ichthyosis survey results were compared with 2021 National Health Interview Survey data for each form of atopy.

Overall, 115 of 130 invited subjects completed surveys. At least 1 physician-diagnosed atopic disorder was reported by 68.2% of the subjects, including 64.3% of the children and 72.5% of the adults. Significantly higher rates of allergic rhinitis, food allergy, and allergic asthma were found in those with congenital ichthyosis than in the age-matched population data. The highest rates were found not only those in with erythrodermic types (Netherton syndrome, ichthyosis with confetti, and harlequin ichthyosis), which is consistent with their higher levels of barrier impairment, but also in those with X-linked ichthyosis (which is characterized by barrier impairment similar to that in atopic dermatitis).

Compared with the general population, patients with congenital ichthyosis have an increased risk of developing allergic disorders, suggesting the value of querying about comorbid allergies as part of routine care.