Cosmetic-Associated Acute Paronychia With Green Nail-Bed Pigmentation in a Child Following Nail Polish Application.

Acute paronychia in children is typically associated with trauma or habitual behaviors, whereas cosmetic-related cases are rarely reported. We describe a 4-year-old girl who developed acute paronychia with persistent green nail-bed pigmentation following the application of nail polish to a nail with pre-existing cuticular disruption. Staphylococcus epidermidis was isolated from purulent discharge, while Pseudomonas aeruginosa was not detected. The clinical course supports a dual pathogenic mechanism involving bacterial invasion through a compromised cuticle and chemical irritation from cosmetic components. The observed green discoloration, confined to the nail bed and occurring in the absence of P. aeruginosa, represents an atypical presentation distinct from classical chloronychia. This case highlights that cosmetic products may represent an underrecognized trigger of nail infections in children, particularly when applied to compromised nail units, and underscores the need for clinician awareness as the use of children's cosmetic products continues to expand.