Multiple sclerosis and psoriasis are autoimmune diseases which share certain immunopathological features. Although the coincidence of the two diseases has not yet been clearly shown to be higher, most meta-analyses suggest so.
In the Czech Republic, only one agent is currently approved in the treatment for which efficacy in both diseases has been demonstrated: dimethyl fumarate. Safety and a possible positive effect on both diseases have been demonstrated in secukinumab and ustekinumab which, however, are not approved to treat multiple sclerosis.
In the case of moderate or severe psoriasis requiring systemic treatment, it is possible - in treating multiple sclerosis - to initiate treatment with glatiramer acetate which has no immunosuppressive effect and exhibits a low risk of interactions with biological therapy. In adjunctive therapy with interferon beta, the safety of methotrexate has been shown, which can also be used in the systemic treatment of psoriasis.
It is advisable to use phototherapy which increases the level of vitamin D. In patients with demyelinating disease, tumour necrosis factor inhibitors are unsuitable since there is a real risk of inducing or deteriorating demyelinating disease in both the peripheral and central nervous systems.
In the case of a severe course of both psoriasis and multiple sclerosis (which, according to available population studies, appears to be a relatively rare phenomenon), cooperation of a neurologist, dermatologist, and immunologist is required given the risk of pharmacodynamic interactions in the case of polytherapy involving immunomodulatory treatment.