OCTREOTIDE SKIN TESTING: A FALSE POSITIVE

Abstract

Introduction Allergic reactions to octreotide are rarely reported in the literature and nonirritating skin testing concentrations have not been established. We present a patient with false-positive skin testing to octreotide. Case Description The patient is a 67 year old female with a pancreatic neuroendocrine tumor who was started on octreotide for control of symptoms related to elevated gastrin secretion. For her first octreotide treatment, patient received 100 mcg subcutaneously. Within ten minutes, patient developed redness at the site of injection and complaints of feeling hot with subsequent development of facial flushing, scalp and ear erythema and epigastric pain. Patient reported that six hours later she developed severe abdominal pain, reflux and bloating. Octreotide skin testing, including prick testing (SPT) and intradermal (ID), was performed. SPT at 50mcg/mL was negative and ID was negative at 0.5 mcg/mL and positive at 5 mcg/mL on patient. ID was repeated on 4 controls at 5 mcg/mL with 2 positive and 2 negative results. The patient underwent a three step graded challenge and subsequently continued monthly doses without further reaction. Discussion Octreotide skin testing has been reported as useful (up to 5 mcg/mL). This case demonstrates that ID octreotide skin testing at 5 mcg/mL can be falsely positive as we had both positive and negative results on control subjects. This highlights the importance of careful clinical history gathering when evaluating patients with drug allergy. Graded challenge is a useful procedure for patients with history of drug allergy, inconclusive skin testing results and low risk of hypersensitivity reaction.