LAS VEGAS – Immunosuppressive drug therapy is not an absolute contraindication for allergy patch testing, according to Dr. Joseph F. Fowler Jr.
A recent report on 11 patients who underwent patch testing while on a variety of systemic immunosuppressive drugs suggested patch testing may be more successful than many clinicians think, Dr. Fowler said. Speaking at the seminar sponsored by Skin Disease Education Foundation (SDEF), he fleshed out the findings with advice from his own experience in patch testing patients on immunosuppressives.
The retrospective chart review included patients on prednisone, cyclosporine, mycophenolate mofetil, or infliximab (Dermatitis 2009;20:265-70).
All but one of the patients who were taking 10 mg/day of prednisone had positive patch test reactions, said Dr. Fowler of the University of Louisville (Ky.) and president of the North American Contact Dermatitis Group.
Dr. Joseph F. Fowler Jr.
"In the past, we had thought that about 10 mg/day was the maximum" prednisone dose that could still allow successful patch testing, but this belief was based on extrapolations of animal studies and case reports, with no hard data, he said. "I have personally seen patients who are on higher doses of prednisone produce good positive reactions."
Ideally, though, it’s best to patch test when patients are off prednisone, or on doses of 10 mg/day or less, he added. "If you could get them on every-other-day prednisone dosing, that would be even better."
For an untreated patient with fairly bad dermatitis, especially on the back, Dr. Fowler may treat for 5-7 days with a corticosteroid, perhaps prednisone 40-60 mg/day with no taper, and then stop the corticosteroid for 2-3 days before patch testing. "That’s one way you can get a person clear enough to patch test them if they’re already broken out," he said.
If the patient already is on chronic corticosteroid therapy, he tries to reduce the dose to 10 mg/day or less for several weeks before patch testing.
Dr. Fowler was surprised patients in the report who were being treated with cyclosporine 200 or 300 mg/day all had positive reactions to patch testing. "Generally, we expect cyclosporine to reduce the likelihood of positive reactions because of its broad immunosuppressant effect," he said. "These folks were on relatively low doses, so maybe that was a factor." In his own experience, Dr. Fowler said he has rarely seen positive reactions to patch testing in patients on cyclosporine, "so I think that’s problematic," he added.
One patient on mycophenolate (CellCept) 2 g/day had a negative result when patch tested but then stopped the drug and had a positive reaction on repeat patch testing. "That would suggest that the CellCept suppressed reactions," Dr. Fowler said. He advised not patch testing patients who are on CellCept, cyclosporine, tacrolimus, or azathioprine if at all possible.
One patient on infliximab (Remicade) whose last infusion occurred 3 weeks before patch testing developed multiple positive reactions. "That mirrors what I’ve been perceiving in clinical practice," he said.
Use of methotrexate or tumor necrosis factor–alpha inhibitors such as Remicade or etanercept (Enbrel) should not prevent patch testing. "I’ve had no problem patch testing people on methotrexate," Dr. Fowler said.
The report did not include antihistamines, which also are not a barrier to patch testing. "Other docs, allergists especially, tell patients they can’t take antihistamines when they’re being patch tested," he explained. "They may not be able to take antihistamines and get a good scratch test result, but remember in patch testing you’re looking at a T cell–mediated process. Antihistamines have essentially no effect on that."
Dr. Fowler has been a consultant, speaker, or researcher for Coria, Galderma, Graceway, Hyland, Johnson & Johnson, Quinnova, Ranbaxy, Shire, Stiefel, Triax, UCB, Medicis, Novartis, Abbott, Taro, Allerderm, Allergan, Amgen, Astellas, Centocor, Dermik, Dow, Genentech, Taisho, and 3M.
SDEF and this news organization are owned by Elsevier.