II. Epidemiology

  1. Most common in young patients
  2. Age under 21 years in 80% of cases
  3. Most common in late summer and fall in the northern United States
  4. Incidence: 22,000 new cases per year in the United States

III. Pathophysiology

  1. Infection by Bartonella Henselae
    1. Previously known as Rochalimaea henselae
    2. Gram Negative Rod
  2. Organism transmitted between cats by the cat flea, Ctenocephalides felis
    1. Can also directly infect humans via its bite
    2. Ticks may also act as vectors
  3. Cats transmit the Bartonella Henselae to humans
    1. Cats transmit the infection via biting or clawing humans
    2. B. henselae lives in feline erythrocytes, and contaminates their Saliva
    3. Present in 50% of cats (who are asymptomatic)

IV. Symptoms

  1. Myalgias
  2. Arthralgias
  3. Malaise
  4. Anorexia
  5. Low-grade fever (uncommon)

V. Signs

  1. Dermatitis at cat scratch or bite
    1. Local Papule, Pustule or Vesicle overlying initial scratch or bite site
  2. Persistent painful regional, ipsilateral Lymphadenopathy (85-90% of cases)
    1. Onset 1-2 weeks after the initial rash, and may persist for months
    2. Overlying reddened skin
    3. Lymph Nodes fluctuant but sterile
    4. Distribution (most commonly involved sites)
      1. Upper extremities at the axilla as well as epitrochlear nodes (nearly half of cases)
      2. Neck and Jaw (one quarter of cases)
      3. Groin

VI. Differential Diagnosis

  1. See Regional Lymphadenopathy
  2. Mycobacterium infection and neoplasm can co-occur with Cat Scratch Disease
    1. Therefore, follow the Lymphadenopathy until resolution

VII. Complications (2%)

  1. Neurologic involvement
    1. Meningoencephalitis
    2. Encephalopathy
      1. Presents as severe Headache and acute confusion at 1-6 weeks after Regional Lymphadenopathy develops
  2. Ocular involvement
    1. Parinaud Oculoglandular Syndrome
      1. Granulomatous Conjunctivitis with periauricular adenopathy
    2. Neuroretinitis
      1. Acute unilateral Visual Field loss secondary to Optic Nerve edema with Macular exudates (star-shaped)
  3. Disseminated Involvement or Bacillary Angiomatosis (immunosuppressed patients)
    1. Bacillary Peliosis can involve the liver and Spleen
    2. Bacillary Angiomatosis can involve bone and skin (red to purple Papules)
  4. Endocarditis


  1. Anti-Bartonella henslae Serology (preferred)
    1. Indirect fluorescent or enzyme-linked immunosorbent assay
    2. IgG titers over 1:256 suggests active or recent infection
      1. Titers 1:64 to 1:256 should be rechecked in 10-14 days
    3. IgM is more specific for acute infection, but poor Test Sensitivity due to very brief IgM production
  2. Excisional Biopsy
    1. Indicated if diagnosis is unclear or if Lymphadenopathy persists
    2. General Findings
      1. Lymphoid Hyperplasia
      2. Stellate Granulomas
      3. Small curved, aerobic, pleomorphic intracellular Rods
      4. Warthin-Starry silver impregnation stain
    3. Findings in Bacillary Angiomatosis
      1. Lobular proliferation of small vessels
      2. Bacilli in adjacent connective tissue
  3. Historical tests
    1. Skin test with Antigen (Hanger-Rose skin test)
  4. Not recommended:
    1. Wound culture
    2. Bartonella PCR (lower sensitivity than Serology, but very specific)
    3. Incision and Drainage

IX. Management : Cat-Scratch Disease

  1. Self limited infection with Lymphadenopathy resolving within 8 weeks and no other sequelae
    1. Antibiotics not required in immunocompetent patients
    2. If antibiotics used, risk of Jarisch-Herxheimer Reaction in first 48 hours of antibiotics
  2. Indications for antibiotic therapy
    1. Most patients are treated to decrease course of infection and reduce complications
    2. Immunocompromised patients
    3. Extra-dermatologic involvement (liver, Spleen, CNS)
      1. See Bacillary Angiomatosis
    4. Moderate involvement
  3. Antibiotics
    1. Azithromycin
      1. Dose: 10 mg/kg up to 500 mg on day 1, and 5 mg/kg up to 250 mg on days 2-5
      2. Lymphadenopathy resolves more readily on Azithromycin
      3. Bass (1998) Pediatr Infect Dis J 17(6): 447-52 [PubMed]
    2. Alternative antibiotics (adult dosing)
      1. Trimethoprim-Sulfamethoxazole DS twice daily for 7-10 days
      2. Rifampin 300 mg orally twice daily for 7 to 10 days
      3. Ciprofloxacin 500 mg orally twice daily for 7-10 days

X. Management: Immunocompromised patients

  1. Bacillary Angiomatosis or Bacillary Peliosis (disseminated or hepatosplenic infection)
    1. See Bacillary Angiomatosis
    2. Duration: 10-14 days up to 3-4 months
    3. Antibiotics: Rifampin and Azithromycin (or Gentamicin)
    4. Corticosteroids are typically used in combination with antibiotics in severe or persistent infections
  2. Neurologic sequelae
    1. Duration: 4-6 weeks
    2. Antibiotics: Rifampin with Doxycycline (or Erythromycin or in children, Trimethoprim-Sulfamethoxazole)
    3. Corticosteroids are typically used in combination with antibiotics

XI. Prevention

  1. Control fleas on the cat and in the environment
  2. Avoid being scratched by cat (home precautions to avoid provoking pets)

XII. Course

  1. Spontaneous resolution common in immunocompetent patients

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Related Studies

Ontology: Cat-Scratch Disease (C0007361)

Definition (MEDLINEPLUS)

Cat scratch disease (CSD) is an illness caused by the bacterium Bartonella henselae. Almost half of all cats carry the infection at some point. The infection does not make cats sick. However, the scratch or bite of an infected cat can cause symptoms in people, including

  • Swollen lymph nodes, especially around the head, neck, and upper limbs
  • Fever
  • Headache
  • Fatigue
  • Poor appetite

For people with weak immune systems, CSD may cause more serious problems. The best way to avoid CSD is to avoid rough play with cats that could lead to scratches or bites. If you do get a scratch or bite, wash it well with soap and water. If the bite or scratch gets infected or if you have symptoms of CSD, call your doctor.

Centers for Disease Control and Prevention

Definition (MSHCZE) Bakteriální onemocnění projevující se zduřením lymfatických uzlin obv. po škrábnutí či kousnutí kočkou. Vyvolavatelem je bakterie Bartonella henselae. Přenos mezi kočkami (zřejmě nikoliv na lidi) způsobují blechy, bakterie se vylučuje do slin. Kočky obv. neonemocní a mohou bakterii dlouhodobě přenášet. Po kousnutí se na kůži vytvoří puchýř či pupen, po době několika týdnů zduří lokální mízní uzliny, které jsou citlivé; někdy mohou zhnisat. Jen menší část nemocných má i celkové příznaky. Nemoc se nepřenáší mezi lidmi. Spontánní průběh trvá týdny až měsíce a obv. je lehký. Nemoc se prokazuje laboratorně (kultivace, kožní testy, histologie uzliny); léčí se, pokud je nutné, antibiotiky. (cit. Velký lékařský slovník online, 2013 http://lekarske.slovniky.cz/ )
Definition (NCI) A bacterial infection caused by Bartonella henselae. It is transmitted to humans from a scratch, bite, or lick from a cat. A blister or a bump appears on the skin following the scratch or bite. Subsequently, there is lymph node enlargement around the scratch or bite site. The lymph node enlargement most often occurs under the arm or the neck. Some patients experience fever, fatigue, headaches or sore throat as well.
Definition (MSH) A self-limiting bacterial infection of the regional lymph nodes caused by AFIPIA felis, a gram-negative bacterium recently identified by the Centers for Disease Control and Prevention and by BARTONELLA HENSELAE. It usually arises one or more weeks following a feline scratch, with raised inflammatory nodules at the site of the scratch being the primary symptom.
Concepts Disease or Syndrome (T047)
MSH D002372
ICD9 078.3
ICD10 A28.1
SnomedCT 123319006, 154370006, 266202002, 79974007
LNC LA10440-8
English Catscratch Disease, Disease, Catscratch, Inoculation Lymphoreticuloses, Inoculation Lymphoreticulosis, Lymphoreticuloses, Inoculation, Lymphoreticulosis, Inoculation, Inoculative Lymphoreticulosis, Inoculative Lymphoreticuloses, Lymphoreticuloses, Inoculative, Lymphoreticulosis, Inoculative, Cat-scratch disease, Disease, Cat-Scratch, CAT SCRATCH DISEASE, CAT SCRATCH DIS, CATSCRATCH DIS, cat scratch disease (diagnosis), cat scratch disease, Benign lyphoreticulosis, Cat-scratch fever, Cat-Scratch Disease [Disease/Finding], scratch cat fever, cat-scratch disease, cat disease scratch, catscratch disease, cat fever scratch, cat scratch fever, Cat Scratch Disease, CSD, Cat scratch disease, Cat scratch fever, Benign inoculation lymphoreticulosis, Benign lymphoreticulosis, CSD - Cat scratch disease, Cat scratch disease (disorder), cat-scratch fever, cat-scratch; disease, catscratch disease or fever, disease (or disorder); cat-scratch, lymphoreticulosis; benign, Cat scratch disease -RETIRED-, Cat-Scratch Disease, Benign lymphoreticulosis, inoculation
Dutch kattenkrabkoorts, lymphoreticulosis benigna, aandoening; kattenkrab, kattenkrab; aandoening, lymforeticulose; benigne, kattenkrabziekte, Kattenkrabziekte, Lymphoreticulosis benigna, Ziekte, kattenkrab-
French Fièvre des griffes de chat, Lymphoréticulose bénigne, Maladie des griffes du chat, Lymphoréticulocytose bénigne, Lymphoréticulose bénigne d'inoculation
German gutartige Lymphoretikulose, Inokulationslymphoretikulose, Katzenkratzkrankheit
Italian Febbre da graffio di gatto, Linforeticolosi benigna, Malattia da graffio di gatto
Portuguese Linforreticulose benigna, Febre de arranhadura do gato, Doença de arranhadura do gato, Linforreticulose Benigna por Inoculação, Linforreticulose de Inoculação, Doença por arranhão de gato, Doença da Arranhadura de Gato, Linforreticulose Benigna de Inoculação
Spanish Fiebre por arañazo de gato, Linforreticulosis benigna, Enfermedad por Rasguño de Gato, enfermedad por arañazo de gato - RETIRADO -, enfermedad por arañazo de gato - RETIRADO - (concepto no activo), Enfermedad por Arañazo de Gato, Linforreticulosis Benigna por Inoculación, enfermedad por arañazo de gato (trastorno), enfermedad por arañazo de gato, fiebre por arañazo de gato, linforreticulosis benigna por inoculación, Enfermedad por arañazo de gato, Linforreticulosis Benigna de Inoculación
Japanese 良性リンパ細網症, ネコ引っかき熱, ネコ引っかき病, ネコヒッカキビョウ, リョウセイリンパサイモウショウ, ネコヒッカキネツ, 細網内皮症-接種リンパ性, ネコひっかき病, 接種リンパ性細網内皮症, 猫引掻き病, 猫爪病, 猫ひっかき病
Swedish Kattklössjuka
Czech nemoc z kočičího škrábnutí, Benigní lymforetikulóza, Horečka z kočičího škrábnutí, Nemoc z kočičího škrábnutí, felinóza
Finnish Kissanraapimatauti
Korean 고양이 찰상병
Polish Choroba kociego pazura
Hungarian Macskakarmolási betegség, Macskakarmolási láz, macskakarmolási betegség, Jóindulatú lymphoreticulosis
Norwegian Katteklorsykdom