Psoriasis may be associated with an increased prevalence of type 1 diabetes (T1D).
Researchers at the University of Padua in Italy performed a small study of 166 consecutive children and adolescents who came through their center from 2017 to 2019 to determine if there was any linkage between the 2 disease. The association between psoriasis and type 2 diabetes is already known.
The researchers found that 13 children (8%) were affected by psoriasis, a prevalence 4 times higher than reported in the general Italian pediatric population (2.1%), according to the study published in the Journal of the European Academy of Dermatology and Venereology.
The authors also noted that in patients with T1D and psoriasis, the onset of clinical symptoms of psoriasis occurred at the same time or after the diagnosis of T1D. They further found the average of hemoglobin A1c (HbA1c) was higher at the onset of psoriasis than at the time of the child’s visit to the center. The finding suggests the potential role of hyperglycemia in the onset of psoriasis in individuals who are predisposed to the disease.
T helper 17 (Th17) cells have been suggested to play a role in the development of T1D, the authors said. Th17-associated cytokines (such as interleukin-17 [IL-17]) reportedly have been higher in patients with T1D than in healthy controls, the authors said.
In patients with psoriasis, poor regulation of skin and systemic inflammation is mainly mediated by Th17 cells; several related cytokines such as IL-17 have been implicated in the development of the disease.
Another hint to the connection between the 2 diseases, the authors said, is the possible overlap in the shared response of psoriasis and T1D to some biologic treatments such as alefacept, a genetically engineered immunosuppressive drug used in treating psoriasis. Alefacept deactivates CD4+ and CD8+ effector memory T cells, thought to be primarily responsible for β cell destruction in T1D. The T1DAL trial demonstrated that the drug triggered changes in effector T cells that prolonged insulin secretion by the remaining β cells in patients newly diagnosed with T1D. Alefacept, which interrupts T cell costimulation and depleting T cells, also is used to treat psoriasis.
The authors also hypothesized that hyperglycemia and psoriasis are related to advanced glycation end products (AGEs), which are compounds produced through oxidation in sugars and are increased in cases of hyperglycemia. AGEs tend to excessively accumulate in the skin and blood of T1D patients and may play a possible role in causing psoriasis through excessive production of free radicals that cause dysregulation in the progress of skin-cell death. Furthermore, some insulin analogues may exacerbate psoriasis.
Central obesity (waist-to-height ratio) was also linked as a factor in patients with T1D developing psoriasis. The study showed 23% of patients with central obesity (5 of 13 patients) had psoriasis, while 8% (5 of 153) did not (P = .04). There was no association, however, for patients who were overweight or obese based on body mass index.
Caroppo F, Galderisi A, Moretti C, et al. Prevalence of psoriasis in a cohort of children and adolescents with type 1 diabetes. J Eur Acad Dermatol Venereol. Published online April 29, 2021. doi:10.1111/jdv.17318.