A 3-year-old with a limp and externally rotated hip is most likely to have what preceding symptom?

In a 3-year-old presenting with a limp and externally rotated hip, the most likely preceding symptom is a recent upper respiratory tract infection. This is particularly relevant in cases such as transient synovitis or Perthes disease, where a child may develop joint symptoms following an upper respiratory infection. The inflammation associated with the upper respiratory tract infection can lead to irritation of the hip joint, resulting in limping and hip discomfort.

While other symptoms like trauma, fever, and weight loss may also be associated with hip issues in children, they are not as closely linked to the presentation of a limp and externally rotated hip related to transient changes following a respiratory illness. Trauma would typically present with more acute and severe pain, fever may suggest an infectious process that is more systemic, and weight loss is usually indicative of chronic or serious pathologies rather than an acute joint issue. Thus, the association with a recent upper respiratory infection stands out as the more likely preceding symptom in this context.