Blocking T helper 1/T helper 17 pathways has no effect on patch testing.

The article presents a case study of a 59-year-old woman who was diagnosed with hydroxyzine-induced hypersensitivity reaction. She has suffered from psoriasis and psoriatic arthritis during her childhood and has been treated with psoralen + ultraviolet A, retinoids, and methotrexate. It states the positive impact of ustekinumab treatment on the patient. Moreover, it notes the failure of the treatment process to prevent the development of her allergic dermatitis caused by hydroxyzine.