Cat-scratch disease

Cat-scratch disease (CSD) or felinosis is an infectious disease that most often results from a scratch or bite of a cat. Symptoms typically include a non-painful bump or blister at the site of injury and painful and swollen lymph nodes. People may feel tired, have a headache, or a fever. Symptoms typically begin within 3–14 days following infection. Cat-scratch disease is caused by the bacterium Bartonella henselae which is believed to be spread by the cat's saliva. Young cats pose a greater risk than older cats. Occasionally dog scratches or bites may be involved. Diagnosis is generally based on symptoms. Confirmation is possible by blood tests. The primary treatment is supportive. Antibiotics speed healing and are recommended in those with severe disease or immune problems. Recovery typically occurs within 4 months but can require a year. About 1 in 10,000 people are affected. It is more common in children. Cat-scratch disease commonly presents as tender, swollen lymph nodes near the site of the inoculating bite or scratch or on the neck, and is usually limited to one side. This condition is referred to as regional lymphadenopathy and occurs 1–3 weeks after inoculation. Lymphadenopathy most commonly occurs in the axilla, arms, neck, or jaw, but may also occur near the groin or around the ear. A vesicle or an erythematous papule may form at the site of initial infection. Most people also develop systemic symptoms such as malaise, decreased appetite, and aches. Other associated complaints include headache, chills, muscular pains, joint pains, arthritis, backache, and abdominal pain. It may take 7 to 14 days, or as long as two months, for symptoms to appear. Most cases are benign and self-limiting, but lymphadenopathy may persist for several months after other symptoms disappear. The disease usually resolves spontaneously, with or without treatment, in one month. In rare situations, CSD can lead to the development of serious neurologic or cardiac sequelae such as meningoencephalitis, encephalopathy, seizures, or endocarditis.