Methylene blue-induced phototoxicity: an unrecognized complication.

OBJECTIVE: To describe photosensitization after prenatal exposure to a toxic amount of methylene blue and to alert pediatricians that, in a review of the literature, photosensitization (which this dye is capable of) has not been reported as a complication of prenatal exposure.

DESIGN AND PATIENTS: A descriptive report of physical findings and significant laboratory tests in a very low birth weight preterm infant with prenatal exposure to methylene blue and a comparison of this reported case with previously described patients' complications and treatment.

SETTING: Neonatal intensive care unit.

INTERVENTION: Monitoring of laboratory tests to assess for methylene blue toxicity: two exchange transfusions for methemoglobinemia, hemolytic anemia, and hyperbilirubinemia; phototherapy for hyperbilirubinemia; and pathologic examination of skin bullae.

RESULTS: Within hours of exposure to phototherapy, redness developed on all exposed areas of the patient's skin (which was initially deep blue), followed by bullae and desquamation of about 35% of the total skin surface area. The desquamation of erythematous areas continued even after discontinuation of phototherapy. Complete re-epithelialization was attained by 3 weeks of age. In addition to this newly observed complication, the patient had other previously described toxic effects.

CONCLUSION: We have reported a previously unrecognized complication associated with high prenatal exposure to methylene blue and treatment with phototherapy. Methylene blue phototoxicity may be related to the high prenatal dose of the dye relative to patient's small size and young gestational age.