5-93
mised, crops of crusted red-purple papules appear.
Cat scratch disease: Variable fever >101°F is accompanied by crusted papule or pustule at inoculation site.
Later: tender, uctuant, regional adenopathy develops, which may last about 3 months (see Color Plates Picture
7). 12% have splenomegaly.
Using Advanced Tools: Lab: The Oroya fever organism can be seen on a peripheral blood smear inside
red blood cells.
Assessment:
Differential Diagnosis:
Kaposi’s sarcoma (KS) - trench fever skin lesions (immunocompromised patients) and Verruga peruana may
resemble disseminated KS, a malignancy seen in immunocompromised hosts with HIV and in elderly men who
live in the Mediterranean area.
Chronic febrile illnesses of the tropics, including Salmonella, malaria, tuberculosis, or brucellosis, may co-exist
with Oroya fever or mimic it. Oroya fever is differentiated by severe anemia and the presence of bacteria in the
red blood cells on blood smear.
The suppurative adenopathy associated with a skin lesion of cat scratch can mimic cutaneous plague, tularemia,
toxoplasmosis, and sporotrichosis infection. Exposure to cat injury helps differentiate.
Plan:
Treatment
Primary:
Oroya fever: Chloramphenicol 2-4 g/d po in divided doses x 7 days
Verruga Peruana: Rifampin 10 mg/kg/day po x 14-21 days
Salmonella is a frequent life-threatening secondary infection, and is often suggested by splenomegaly. Infection
during pregnancy can result in fetal death or abortion.
Trench fever: Aspirin prn, doxycycline 100 mg po qd x 15 days
Cat scratch disease: Azithromycin 500 mg po day 1, then 250 mg po qd x 4 days; analgesics
Alternate:
Oroya Fever: Doxycycline or ampicillin
Cat Scratch Disease: Give no treatment and infection self-resolves in 2-6 months
Patient Education
General: Oroya fever - watch for late development of skin verruca. Cat scratch disease-- apply heat locally
for pain relief
Activity: As tolerated
Diet: Regular
Prevention and Hygiene: Oroya fever - use personal prevention methods during the nocturnal biting cycle of
sandy while in endemic areas. Trench fever – control body lice; use good personal hygiene.
Cat scratch disease - avoid playing with unknown cats, especially kittens.
No Improvement/Deterioration: Return if fever persists for more than one week or if (cat scratch disease)
lymph nodes start to drain pus.
Follow-up Actions
Return evaluation: Cat Scratch Disease - Relieve pain in uctuant lymph node with needle aspiration; avoid
incision and drainage.
Evacuation/Consultation Criteria: Evacuation is not usually necessary, but may be indicated for some unstable
patients. Serology is available on acute and convalescent serum at referral centers to conrm diagnoses.
Zoonotic Disease Considerations
Cat Scratch Fever
Principal Animal Host: Cats
Clinical Disease in Animals: Asymptomatic carriers
Known Distribution: Worldwide