What would be considered a concerning sign if a child presents with bruising and purpura?

The presence of a fever in a child with bruising and purpura is a concerning sign as it may indicate an underlying infection or systemic condition that warrants further investigation. Fever can be associated with conditions such as vasculitis, severe infections, or hematological disorders like thrombocytopenia. When evaluating bruising and purpura in a pediatric patient, the presence of a fever raises suspicion for conditions that could affect platelet function or blood vessel integrity, leading to bleeding manifestations.

The other signs listed – lack of swelling in the joints, low body temperature, and normal urinalysis – do not carry the same level of concern in this specific context. A lack of swelling in the joints may suggest the absence of traumatic injury or inflammatory joint disease but doesn’t necessarily correlate with the severity of the bleeding. A low body temperature might indicate a different set of issues such as infection or metabolic problems but isn't directly related to the bruising and purpura. Meanwhile, a normal urinalysis typically suggests there are no renal systemic issues; though it does provide some reassurance, it does not eliminate the need for careful assessment when bruising is present.