Abstract
Pseudogout or calcium pyrophosphate dihydrate deposition disease rarely occurs in the young. Known risk factors for pseudogout include age, previous surgery, trauma, metabolic conditions, and medications. Isotretinoin, a retinoid frequently used to control acne vulgaris, is known to cause arthralgia, arthritis, and myalgia. We describe a case of an adolescent using isotretinoin who presented with acute left upper extremity pain and weakness. Birefringent calcium pyrophosphate dihydrate crystals were seen on synovial fluid analysis. The patient's symptoms resolved after discontinuing isotretinoin. This is the first reported case of pseudogout in an adolescent on isotretinoin.