Managing Pruritus: Steroids & Beyond

To successfully treat pruritus, it is important to address underlying causes and secondary factors. Flea bite dermatitis and flea bite hypersensitivity are the most common pruritic skin diseases affecting dogs and cats. Additional parasitic causes include Sarcoptes spp, Cheyletiella spp, and Demodex spp infection. 

Staphylococcus spp, Malassezia pachydermatis, and dermatophyte infections must be controlled. Allergen-specific immunotherapy is the only therapy that can modify or reverse the pathogenesis of atopic dermatitis. Recombinant technology is a recent development in allergen-specific immunotherapy, as are novel routes of administration (eg, sublingual, intralymphatic). Variable response has been seen with antihistamine treatment.

Corticosteroids have down-regulatory effects in the inflammatory cascade; adverse effects are possible. Corticosteroids are most effective in managing acute flare-ups to break the itch-scratch cycle. Dosages should be tapered.

Cyclosporine is steroid sparing and can be as effective as steroids against pruritus. However, the onset of cyclosporine is slow, and GI side effects are common. Oclacitinib inhibits the IL-31 cytokine function and has additional immunomodulatory effects. Its rapid onset makes it useful for pruritus flare-ups. Adverse effects with chronic use include demodicosis, pneumonia, and other immunosuppressive effects.

Caninized anti-cIL31 monoclonal antibodies have rapid onset, are effective for 4 to 6 weeks, and have no known side effects or drug interactions. Long-term safety and efficacy data are lacking.