OBJECTIVES: The TEN-4-FACESp bruising clinical decision rule (BCDR) is a validated screening tool utilizing information about a child's body region bruised, age, and pattern of bruising to predict abuse in children younger than 4 years of age. Our objectives were to (1) evaluate the accuracy of the BCDR in predicting abuse when only 1 bruise was present and (2) identify other characteristics differentiating abusive from accidental injury in young children with a single bruise. METHODS: Patients included in this secondary analysis were those from the BCDR validation study whose only skin finding was a single bruise (including petechiae, subconjunctival hemorrhage, or frenulum injury). Cases were previously classified as abuse, accident, or indeterminate by an expert panel. We compared demographics, clinical characteristics, bruising regions, and psychosocial risk factors (PRFs) between abuse and accident groups. RESULTS: Of 349 patients with a single bruise, 27 were classified as abuse. The TEN-4-FACESp BCDR performed with 81.5% sensitivity and 87.6% specificity in this sample. Patients with abusive injuries were (1) younger and (2) less likely to present with an injury complaint but more likely to (3) have a bruise in a BCDR-positive region, (4) have a lower Glasgow Coma Score, and (5) have PRFs. CONCLUSIONS: The TEN-4-FACESp BCDR is an effective screening tool for abuse among young children with a single bruise in the pediatric ED. Even 1 BCDR-positive bruise indicated increased risk for abuse. Negative BCDR results must be interpreted with caution given the higher rate of false negatives in this analysis compared with the validation study.