What infection is associated with localized papules and ipsilateral regional lymphadenopathy in a child who has had cat exposure?

The presence of localized papules and ipsilateral regional lymphadenopathy in a child with a history of cat exposure is highly indicative of cat-scratch disease. This condition, caused by the bacterium Bartonella henselae, often arises after a scratch or bite from an infected cat. In typical cases, the initial papule at the site of the scratch or bite can be followed by the development of swollen lymph nodes on the same side of the body, leading to regional lymphadenopathy.

Cat-scratch disease is characterized by these symptoms, and it commonly affects children, particularly those who have close interactions with cats. The pattern of localized skin findings (such as papules) along with the swollen lymph nodes supports the diagnosis, making it distinct from other listed options. In contrast, lymphogranuloma venereum is associated with different modes of transmission and typically presents with a different clinical picture, while feline leukemia virus primarily affects cats and would not produce the localized symptoms described in this scenario. Ringworm, a fungal infection, usually presents with circular patches of hair loss and would not cause ipsilateral lymphadenopathy in the way that cat-scratch disease does.