Hamann et al. reported a psoriasis patient in treatment with secukinumab (a human IgG1κ monoclonal antibody that binds to IL-17A) who developed pruritic dermatitis on the hands, arms, legs, and trunk and presented with a positive patch test to the emulsifier sorbitan sesquioleate, and the reactions to fragrance mix I and cinnamic aldehyde were deemed to be attributable to its presence in these patch test products. The gene discussed is IL17A; the disease is psoriasis.