In considering the limits of age, the pediatric population also has been studied regarding salicylate toxicity. Most commonly, oral ingestion has caused fatalities, as oil of wintergreen has been cited as extremely dangerous for children if swallowed; doses as small as a teaspoon (5 mL: 7000 mg salicylate) have resulted in fatalities.4,6 Although the consumption of a large amount of a cream- or ointment-based product is unlikely due to the consistency of the medication,6 the thought does merit consideration in the inquisitive toddler age group. For a 15-kg toddler, 150 mg/kg of aspirin or 2250 mg of aspirin, is considered the toxic level, which upon conversion to methyl salicylate levels using a 1.4 factor equates to 1607 mg of methyl salicylate to reach toxicity.6 If using a product with methyl salicylate 30% composition, 1 g of the product contains 300 mg of methyl salicylate; therefore if the toddler consumed approximately 5.3 g of the product (1607 mg methyl salicylate [toxic level] divided by 300 mg methyl salicylate per 1 g of product), he/she would reach toxic levels.6,11 To put this into perspective, a 2-oz tube contains 57 g (approximately 10 times the toxic dose) of the product.8 Thus, although there is less concern overall for consumption of cream- or ointment-based methyl salicylate, there still is potential for harm if a small child were to ingest such a product containing higher percentages of methyl salicylate.6
There also have been reports of pediatric toxicity related to percutaneous absorption, even leading to pediatric fatality.4,6 In particular, there was a case of a young boy hospitalized with ichthyosis who received escalating doses of percutaneous salicylate, which resulted in toxicity; when therapy was discontinued, he experienced full recovery.12 In 2007, a 17-year-old adolescent girl died from methyl salicylate toxicity after numerous applications of salicylate-containing products in conjunction with medicated pads.7
Although the FDA has drawn attention and encouraged caution with use of OTC topical musculoskeletal pain relievers, the importance of ensuring patients are fully aware of potential burns, permanent skin or muscle damage, and even death if used inappropriately cannot be overstated. The FDA consumer health information website has 2 patient-directed handouts2,3 that may be useful to post in patient waiting areas to increase overall understanding of the risks associated with OTC products containing methyl salicylate and menthol ingredients. Fortunately, our patient suffered only mild postinflammatory hyperpigmentation without substantial sustained consequences.