Cat Allergy as a Source Intensification of Atopic Dermatitis in Adult Patients

Atopic dermatitis (AD) is characterized by exacerbations and remissions of eczematous skin, underlain by impaired skin barrier and aberrant Th2-type and Th-22 cytokine production. A number of allergens, in particular contact with fur animals, may aggravate the disease. This study seeks to define the influence of having a regular contact with a pet cat at home on the severity of symptoms and signs of AD. We addressed the issue using the SCORing Atopic Dermatitis (SCORAD) and visual analog (VAS) scores to assess the intensity of pruritus and by measuring the blood content of specific IgE and IL-4, IL-13, and IL-22 cytokines. The study group consisted of 47 adult patients suffering from AD since childhood, 18 of whom declared having regular contact with a cat and the remaining 29 who denied it. There also was a control group consisted of 16 healthy volunteers with no AD signs. The SCORAD and VAS scores were significantly higher in patients in contact with a cat than in those without it (median SCORAD 61.0 vs. 50.4 and VAS 9.0 vs. 4.0 points, respectively). The sIgE of a majority of patients (94.4%) in contact with a cat was in Class V-VI, compared with just a few patients (3.4%) with no such contact, having sIgE in the same classes (p < 0.001). Significant correlations were revealed between SCORAD and VAS scores and the class level of serum sIgE value. In addition, IL-22 was a single elevated cytokine, only in the patients in contact with a cat, and it correlated with pruritus severity. The results of the study underline the need to beware of the cat fur allergen, and they stress forethought and caution in acquiring and keeping a pet cat by patients suffering from AD.