a case of allergic diaper dermatitis in a 1-year-old boy, caused by benzothiazoles (mercapto compounds).
CASE REPORTA 1-year-old male infant presented with a 4-week-history of diaper rash, being otherwise healthy. Physical examination revealed oval, sharply demarcated erythematous and exudative plaques on his upper thighs. Some scattered erythematous papules were also observed on the pubic and perineal area (Figure 1). Over 1 week, the lesions gradually improved with oral cetirizine and topical zinc oxide. We performed patch tests with the AL test (Euromedical, Calolziocorte, Italy) on Scanpor tape (Norgesplaster, Vennesla, Norway) fixed on the back with Hypafix (BSN Medical, Hamburg, Germany) with an occlusion time of 2 days. The patient was tested with allergens potentially contained in the disposable diapers and diaper wipes in use, including thiuram mix 1% pet., colophonium 20% pet., mercapto mix 2% pet., fragrance mix I 8% pet., mercaptobenzothiazole (MBT) 2% pet., methylchloroisothiazolinone/ methylisothiazolinone (0.02% aq.), fragrance mix II 14% pet. and p-tertbutylphenol formaldehyde resin (PTBFR) 1% pet. Patch tests showed a + + reaction on day (D) 2 and D 4 to both mercapto mix and MBT. After switching diapers, the lesions totally disappeared without relapses.
DISCUSSIONIrritant contact dermatitis with maceration and breakdown of the skin barrier caused by urine and feces is a common dermatological problem in the diapered pediatric population. Because damaged skin facilitates the penetration of potential allergens, chronic allergic contact dermatitis with a "swimsuit distribution" in diapered infants can ensue. 4 The most common potential allergens in diapers include botanical extracts, alpha-tocopherol, fragrances, propylene glycol, parabens, iodopropynyl butylcarbamate, and lanolin. 4Moreover, contact dermatitis from diapers due to rubber chemicals (mercaptobenzothiazole) or glues such as PTBFR has been reported. In these cases the eczematous lesions are located on the outer buttocks and hips (named "Lucky Luke" contact dermatitis for the particular distribution of eczema recalling a cowboy's gun belt holster) or in the upper thighs corresponding to elastic borders of the diaper. 1-6 In our case, the clinical history and the initial presentation of the lesions in the perineal area and inguinal folds were suggestive for an irritant diaper dermatitis that had probably facilitated penetration of allergens and led to a contact allergy from rubber chemicals. Accordingly, patch testing was performed and was positive for both mercapto mix and MBT. However, DI ALTOBRANDO ET AL. 71 it was impossible to trace back all the chemical products contained in the diapers in use. Thus, we cannot exclude that other possible rubber band materials played a role in the allergic reaction of our patient.A recent editorial has pointed to the lack of communication with, and cooperation from, the manufacturers of medical devices regarding the labeling of ingredients. 7 Although diapers cannot be considered medical devices ...