We thank Dr Kay and colleagues for their comments regarding the control for the effects of psoriatic arthritis in quality-of-life research in psoriasis. Specific impairments reported by patients with psoriasis, such as pain and stiffness, and specific limitations in the performance of daily activities, such as rising, dressing, walking, reaching, and gripping, are likely to be related to the inflammatory arthritis rather than the cutaneous psoriasis. Additionally, problems with psychological and social functioning have been described in patients with various types of psoriasis, in inflammatory arthritis, as well as in psoriatic arthritis.1- 3 Therefore, in the study of quality of life in patients with psoriasis, inflammatory arthritis can indeed be considered as a confounding variable.
de Korte J, Bos JD. Effects of Inflammatory Arthritis on Quality of Life in Patients With Psoriasis—Reply. Arch Dermatol. 2003;139(12):1655-1656. doi:10.1001/archderm.139.12.1655-a