[Local salicylate transcutaneous absorption: an unrecognized risk of severe intoxication: a case report]

Although rare, salicylate intoxication through the skin should not be ignored as it can be severely life-threatening. We describe an original case of accidental poisoning with salicylates topically applied to the scalp of a 6-week-old infant.

A 6-week-old infant, with no prior history, was admitted to the pediatric intensive care unit for treatment of severe disorders of consciousness associated with significant tachypnea. Laboratory results revealed metabolic acidosis with elevated anion gap, ketonuria, and normal glycemia. Initial assessment ruled out the hypothesis of accidental ingestion of salicylates. However, the presence of salicylic acid derivatives in organic acid chromatography, confirmed by plasma salicylate levels at 580 mg/L, ultimately re-established the diagnosis. Further inquiry retrospectively highlighted the prolonged topical application in occlusion (3 days) of an extemporaneous preparation containing 23% salicylic acid on the scalp. The course after urine alkalinization was rapidly favorable without sequelae.

Salicylate intoxication is potentially lethal, particularly in infants under 12 months of age. The vast majority of these intoxications result from accidental ingestion. The present observation underscores the original and undescribed risk of intoxication due to a localized application to the scalp. In the presence of warning symptoms, salicylate poisoning should be investigated, including topical application of salicylic acid, even if localized. Careful attention should be paid to following the indications of use of this product in terms of concentration, characteristics of the infant, and exposed skin. The use of extended topical application of salicylic acid in concentrations greater than 3% should be avoided.