Cat-scratch disease is a benign and self-limited bacterial infection of Bartonella henselae. It is characterized in most cases by a primary papulopustular skin lesion and enlarged localized lymph nodes, with a history of cat contact proximal to the involved node. Fatigue, malaise, pharyngitis, conjunctivitis, headache, and low-grade fever may be present. Following inoculation, incubation periods are generally a few days to several weeks.

Dermatologic involvement is seen in approximately two-thirds of patients and includes evidence of a scratch without or with a papulopustular lesion, a widespread morbilliform eruption, erythema nodosum (warm, erythematous, and painful nodules in lower extremities), erythema multiforme, and/or thrombocytopenic purpura. Splenomegaly, weight loss, and parotid swelling rarely appear.

In two-thirds of patients, the lesion lasts for less than a month, although it may persist for 2 months or more in some cases. Nodes are tender, gradually increase in size, become erythematous and fluctuant, and may become suppurative. Most patients recover without sequelae. Encephalitis may occur in 1%-7% of cases, typically appearing 2-6 weeks after classic cat-scratch disease. Patients may present with associated seizures or status epilepticus.

The eye is involved in less than 10% of cases. Presentation is typically unilateral with either granulomatous conjunctivitis ("pink eye"), eyelid lesions (papules, pustules), or decreased vision from posterior ocular involvement.

The two most common ocular syndromes include oculoglandular syndrome of Parinaud (OSP) and neuroretinitis. OSP includes lymphadenopathy and a follicular conjunctivitis. Neuroretinitis includes inflammation of the optic nerve and macula.