To manage the reaction, “I have sometimes tried getting prednisone or cyclosporine in there right away just to get immediate control because these patients get so bad so quickly, and then [I] start another form of therapy.”
Interferon: Pyoderma Gangrenosum
Although not common, the development of virulent pyoderma gangrenosum-type ulcers at the interferon injection sites of some patients receiving the drug for multiple sclerosis or hepatitis C, “appears to be the result of interferon aggravating one of the TH1 types of inflammatory processes that typically occurs within 3 months of starting the therapy,” Dr. Heald said. Biopsies of the affected areas may show neutrophil infiltrates of vasculitis.
“Because patients and their neurologists love the drug, they're not going to stop it, so they will want you to help manage them through it,” Dr. Heald said. This is particularly true for patients with multiple sclerosis. “Patients who are staying on interferon for MS can be taught how to do interlesional triamcinolone injections, which I've had the most success with.”
Vitiligo and Imiquimod
Topical imiquimod can induce local interferon-α release and vitiligo hypopigmentation. “In patients prone to vitiligo, the imiquimod triggers an immunomodulating event that may enhance a latent cell-mediated process,” Dr. Heald said. “In the patients I've treated with this condition, nobody has developed vitiligo all over. It's been localized to the area of imiquimod application.” Use one of the other topical immunomodulator drugs, he said.
Infliximab and Lupus Erythematosus
Four months on infliximab appears to bring out subclinical lupus in a small percentage of patients with preexisting antinuclear antibodies.
“I've had about a half-dozen patients who are on infliximab for rheumatoid arthritis coming in with a lupus-like syndrome of anular, flat, scaly skin lesions that tend to be mostly on the face and arms,” Dr. Heald said.
“The mechanism for the condition is a little bit murky, but what's clear is that in some systems with an ongoing autoimmune process, the anti-TNF action can exacerbate disease,” Dr. Heald said. “In these instances, you have to stop the drug. You can't treat through this.”
Alternative treatment options include methotrexate or thiopurines. “You want to stay away from the anti-TNF family in general,” he said, noting that once infliximab therapy is withdrawn, the skin lesions tend to clear in 2–3 months.