Patch Test Clinic Start-up: From Basics to Pearls

Methotrexate and Patch Testing: A Retrospective Review

“…As a result, there are defined guidelines on when to discontinue before patch testing. 1,2,[5][6][7] Other immunosuppressants, such as mycophenolate and tacrolimus, have a smaller body of evidence with very few cases of patch testing reported while on these medications. [8][9][10] Nevertheless, a survey of expert opinion suggests that they cause dose-dependent inhibition.…”

“…Robust evidence exists that corticosteroids can suppress patch test reactions. As a result, there are defined guidelines on when to discontinue before patch testing 1,2,5–7 . Other immunosuppressants, such as mycophenolate and tacrolimus, have a smaller body of evidence with very few cases of patch testing reported while on these medications 8–10 .…”

“…Limited published literature suggests that certain immunosuppressants may cause "falsenegative readings." 1,2 However, immunosuppressant therapy is required to control another medical condition or to reduce cutaneous inflammation for patch test placement. Thus, there is a need to characterize the degree to which different medications can suppress patch test reactions.…”

“…Patch tests have long been crucial in evaluating suspected allergic contact dermatitis because of their ability to identify type IV hypersensitivity reactions to specific allergens. Limited published literature suggests that certain immunosuppressants may cause “false-negative readings.” 1,2 However, immunosuppressant therapy is required to control another medical condition or to reduce cutaneous inflammation for patch test placement. Thus, there is a need to characterize the degree to which different medications can suppress patch test reactions.…”

Allergic Patch Testing in Dermatology

“…For a liquid allergen, 15 µL of the preparation is blotted onto a filter paper, which is then placed on to the chambers. [1] One must be cautious as an excessive amount of allergen can increase the risk of sensitisation.…”