Psoriasis is a chronic immunologically-mediated inflammatory disease characterized by scaly, erythematous plaques, primarily affecting the extensor surfaces and involving the IL-23/Th17 pathway. It is associated with increased risks for arthritis, cardiovascular issues, and other autoimmune disorders.

This case discusses a 27-year-old Filipino female with a 7-year history of psoriasis, initially treated with clobetasol ointment, methotrexate, and narrowband UVB phototherapy. Due to worsening of lesions, patient eventually developed erythrodermic psoriasis and was treated with secukinumab, an IL-17 inhibitor. While on biologic treatment, patient experienced weight loss, diarrhea, hand tremors, palpitations, and fatigue. Patient was worked up, showing elevated FT3, FT4, and TSH receptor antibody leading to a diagnosis of Graves’ Disease.

Research shows increased risk of thyroid dysfunction in psoriasis patients, with greater association with Hashimoto Thyroiditis than Graves’ Disease. The highest ratio of thyroid involvement concerning dermatologic subtypes was 59% for erythrodermic psoriasis.

The connection between psoriasis and Graves’ Disease may stem from a shared T-helper 1 response and IL-17 involvement in the IL-23/Th17 axis. Research indicates an elevated Th17 proportion in Graves’ patients, suggesting that blocking IL-17 might reduce inflammation. However, in this case, contrary to this, a new onset autoimmune condition developed despite the use of an IL-17 inhibitor.

This case underscores the need for a multidisciplinary approach in managing chronic immunologic disorders like psoriasis, which can impact multiple organ systems beyond the skin. This case may help explore the connection of psoriasis with other autoimmune conditions.