Cat-scratch disease

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Cat scratch disease
SynonymsCat-scratch fever, Teeny's disease, inoculation lymphoreticulosis, subacute regional lymphadenitis [1]
An enlarged lymph node in the armpit region of a person with cat-scratch disease, and wounds from a cat scratch on the hand.
Specialty Infectious disease
SymptomsBump at the site of the bite or scratch, swollen and painful lymph nodes [2]
Complications Encephalopathy, parotitis, endocarditis, hepatitis [3]
Usual onsetWithin 14 days after infection [2]
Causes Bartonella henselae from a cat bite or scratch [2]
Diagnostic method Based on symptoms, blood tests [3]
Differential diagnosis Adenitis, brucellosis, lymphogranuloma venereum, lymphoma, sarcoidosis [3]
Treatment Supportive treatment, antibiotics [2] [3]
PrognosisGenerally good, recovery within 4 months [3]
Frequency1 in 10,000 people [3]

Cat-scratch disease (CSD) is an infectious disease that results from a scratch or bite of a cat. [4] Symptoms typically include a non-painful bump or blister at the site of injury and painful and swollen lymph nodes. [2] People may feel tired, have a headache, or a fever. [2] Symptoms typically begin within 3-14 days following infection. [2]

Cat domesticated feline

The cat is a small carnivorous mammal. It is the only domesticated species in the family Felidae and often referred to as the domestic cat to distinguish it from wild members of the family. The cat is either a house cat, kept as a pet, or a feral cat, freely ranging and avoiding human contact. A house cat is valued by humans for companionship and for its ability to hunt rodents. About 60 cat breeds are recognized by various cat registries.

Fever common medical sign characterized by elevated body temperature

Fever, also known as pyrexia and febrile response, is defined as having a temperature above the normal range due to an increase in the body's temperature set point. There is not a single agreed-upon upper limit for normal temperature with sources using values between 37.5 and 38.3 °C. The increase in set point triggers increased muscle contractions and causes a feeling of cold. This results in greater heat production and efforts to conserve heat. When the set point temperature returns to normal, a person feels hot, becomes flushed, and may begin to sweat. Rarely a fever may trigger a febrile seizure. This is more common in young children. Fevers do not typically go higher than 41 to 42 °C.


Cat-scratch disease is caused by the bacterium Bartonella henselae which is believed to be spread by the cat’s saliva. [2] Young cats pose a greater risk than older cats. [3] Occasionally dog scratches or bites may be involved. [3] Diagnosis is generally based on symptoms. [3] Confirmation is possible by blood tests. [3]

<i>Bartonella henselae</i> species of bacterium

Bartonella henselae, formerly Rochalimæa, is a proteobacterium that is the causative agent of cat-scratch disease (bartonellosis).

The primary treatment is supportive. [3] Antibiotics speed healing and are recommended in those with severe disease or immune problems. [2] [3] Recovery typically occurs within 4 months but can require a year. [3] About 1 in 10,000 people are affected. [3] It is more common in children. [4]

Signs and symptoms

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. [5] Lymphadenopathy in CSD most commonly occurs in the arms, neck, or jaw, but may also occur near the groin or around the ear. [4] A vesicle or an erythematous papule may form at the site of initial infection. [4] Most patients also develop systemic symptoms such as malaise, decreased appetite, and aches. [4] 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. [4] The disease usually resolves spontaneously, with or without treatment, in one month.

Lymphadenopathy disorder of lymph nodes

Lymphadenopathy or adenopathy is disease of the lymph nodes, in which they are abnormal in size, number, or consistency. Lymphadenopathy of an inflammatory type is lymphadenitis, producing swollen or enlarged lymph nodes. In clinical practice, the distinction between lymphadenopathy and lymphadenitis is rarely made and the words are usually treated as synonymous. Inflammation of the lymphatic vessels is known as lymphangitis. Infectious lymphadenitis affecting lymph nodes in the neck is often called scrofula.

Erythema symptom

Erythema is redness of the skin or mucous membranes, caused by hyperemia in superficial capillaries. It occurs with any skin injury, infection, or inflammation. Examples of erythema not associated with pathology include nervous blushes.


A papule is a circumscribed, solid elevation of skin with no visible fluid, varying in area from a pinhead to 1 cm. It can be brown, purple, pink or red in color, and can cluster into a papular rash. Papules may open when scratched and become infected and crusty. Larger non-blisterform elevated lesions may be termed nodules.

In rare situations, CSD can lead to the development of serious neurologic or cardiac sequelae such as meningoencephalitis, encephalopathy, seizures, or endocarditis. [4] Endocarditis associated with Bartonella infection has a particularly high mortality. [5] Parinaud's oculoglandular syndrome is the most common ocular manifestation of CSD, [4] and is a granulomatous conjunctivitis with concurrent swelling of the lymph node near the ear. [6] Optic neuritis or neuroretinitis is one of the atypical presentations. [7]

Meningoencephalitis central nervous system disease that involves encephalitis which occurs along with meningitis

Meningoencephalitis, also known as herpes meningoencephalitis, is a medical condition that simultaneously resembles both meningitis, which is an infection or inflammation of the meninges, and encephalitis, which is an infection or inflammation of the brain.

Encephalopathy means any disorder or disease of the brain, especially chronic degenerative conditions. In modern usage, encephalopathy does not refer to a single disease, but rather to a syndrome of overall brain dysfunction; this syndrome can have many different organic and inorganic causes.

Endocarditis endocardium disease characterized by inflammation of the endocardium of the heart chambers and valves

Endocarditis is an inflammation of the inner layer of the heart, the endocardium. It usually involves the heart valves. Other structures that may be involved include the interventricular septum, the chordae tendineae, the mural endocardium, or the surfaces of intracardiac devices. Endocarditis is characterized by lesions, known as vegetations, which is a mass of platelets, fibrin, microcolonies of microorganisms, and scant inflammatory cells. In the subacute form of infective endocarditis, the vegetation may also include a center of granulomatous tissue, which may fibrose or calcify.

People who are immunocompromised are susceptible to other conditions associated with B. henselae and B. quintana, such as bacillary angiomatosis or bacillary peliosis. [4] Bacillary angiomatosis is primarily a vascular skin lesion that may extend to bone or be present in other areas of the body. In the typical scenario, the patient has HIV or another cause of severe immune dysfunction. Bacillary peliosis is caused by B. henselae that most often affects patients with HIV and other conditions causing severe immune compromise. The liver and spleen are primarily affected, with findings of blood-filled cystic spaces on pathology. [8]

Bacillary angiomatosis human disease

Bacillary angiomatosis (BA) is a form of angiomatosis associated with bacteria of the genus Bartonella.

Bacillary peliosis is a form of peliosis hepatis that has been associated with bacteria in the genus Bartonella.

HIV/AIDS Spectrum of conditions caused by HIV infection

Human immunodeficiency virus infection and acquired immune deficiency syndrome (HIV/AIDS) is a spectrum of conditions caused by infection with the human immunodeficiency virus (HIV). Following initial infection, a person may not notice any symptoms or may experience a brief period of influenza-like illness. Typically, this is followed by a prolonged period with no symptoms. As the infection progresses, it interferes more with the immune system, increasing the risk of developing common infections such as tuberculosis, as well as other opportunistic infections, and tumors that rarely affect people who have uncompromised immune systems. These late symptoms of infection are referred to as acquired immunodeficiency syndrome (AIDS). This stage is often also associated with unintended weight loss.


Bartonella henselae is a fastidious, [5] intracellular, Gram-negative bacterium.


The cat was recognized as the natural reservoir of the disease in 1950 by Robert Debré. [5] Kittens are more likely to carry the bacteria in their blood, so may be more likely to transmit the disease than adult cats. However, fleas serve as a vector for transmission of B. henselae among cats, [5] and viable B. henselae are excreted in the feces of Ctenocephalides felis , the cat flea. [9] Cats could be infected with B. henselae through intradermal inoculation using flea feces containing B. henselae. [10] As a consequence, a likely means of transmission of B. henselae from cats to humans may be inoculation with flea feces containing B. henselae through a contaminated cat scratch wound or by cat saliva transmitted in a bite. [5] Ticks can also act as vectors and occasionally transmit the bacteria to humans. [4] Combined clinical and PCR-based research has shown that other organisms can transmit Bartonella, including spiders. [11] [12] Cryptic Bartonella infection may be a much larger problem than previously thought, constituting an unrecognized occupational health hazard of veterinarians. [13]


Micrograph of a lymph node affected by cat scratch disease. H&E stain. Cat scratch disease - very low mag.jpg
Micrograph of a lymph node affected by cat scratch disease. H&E stain.
High-magnification micrograph of CSD showing a granuloma (pale cells - right of center on image) and a microabscess with neutrophils (left of image), H&E stain Cat scratch disease - very high mag.jpg
High-magnification micrograph of CSD showing a granuloma (pale cells - right of center on image) and a microabscess with neutrophils (left of image), H&E stain

The Warthin–Starry stain can be helpful to show the presence of B. henselae, but is often difficult to interpret. B. henselae is difficult to culture and can take 2–6 weeks to incubate. [5] The best diagnostic method available is polymerase chain reaction, which has a sensitivity of 43-76% and a specificity (in one study) of 100%. [5]


Cat-scratch disease is characterized by granulomatous inflammation on histological examination of the lymph nodes. Under the microscope, the skin lesion demonstrates a circumscribed focus of necrosis, surrounded by histiocytes, often accompanied by multinucleated giant cells, lymphocytes, and eosinophils. The regional lymph nodes demonstrate follicular hyperplasia with central stellate necrosis with neutrophils, surrounded by palisading histiocytes (suppurative granulomas) and sinuses packed with monocytoid B cells, usually without perifollicular and intrafollicular epithelioid cells. This pattern, although typical, is only present in a minority of cases. [14]


Cat-scratch disease can be primarily prevented by taking flea control measures and washing hands after handling a cat or cat feces; since cats are mostly exposed to fleas when they are outside, keeping cats inside can help prevent infestation. [15]


Most healthy people clear the infection without treatment, but in 5 to 14% of individuals, the organisms disseminate and infect the liver, spleen, eye, or central nervous system. [16] Although some experts recommend not treating typical CSD in immunocompetent patients with mild to moderate illness, treatment of all patients with antimicrobial agents (Grade 2B) is suggested due to the probability of disseminated disease. The preferred antibiotic for treatment is azithromycin, since this agent is the only one studied in a randomized controlled study. [17]

Azithromycin is preferentially used in pregnancy to avoid the teratogenic side effects of doxycycline. [18] However, doxycycline is preferred to treat B. henselae infections with optic neuritis due to its ability to adequately penetrate the tissues of the eye and central nervous system. [5]


Cat-scratch disease has a worldwide distribution, but it is a nonreportable disease in humans, so public health data on this disease are inadequate. [19] Geographical location, present season, and variables associated with cats (such as exposure and degree of flea infestation) all play a factor in the prevalence of CSD within a population. [20] In warmer climates, the CSD is more prevalent during the fall and winter, [20] which may be attributed to the breeding season for adult cats, which allows for the birth of kittens [20] . B henselae, the bacterium responsible for causing CSD, is more prevalent in younger cats (less than one year old) than it is in adult cats. [19]

To determine recent incidence of CSD in the United States, the Truven Health MarketScan Commercial Claims and Encounters database was analyzed in a case control study from 2005-2013. [21] The database consisted of healthcare insurance claims for employees, their spouses, and their dependents. All participants were under 65 years of age, from all 50 states. The length of the study period was 9 years and was based on 280,522,578 person-years; factors such as year, length of insurance coverage, region, age, and sex were used to calculate the person-years incidence rate to eliminate confounding variables among the entire study population. [21] A total of 13,273 subjects were diagnosed with CSD, and both in- and outpatient cases were analyzed. The study revealed an incidence rate of 4.5/100,000 outpatient cases of cat-scratch disease. For inpatient cases, the incidence rate was much lower at 0.19/100,000 population. [21] Incidence of CSD was highest in 2005 among outpatient cases and then slowly declined. The Southern states had the most significant decrease of incidence over time. Mountain regions have the lowest incidence of this disease because fleas are not commonly found in these areas. [21]

Distribution of CSD among children aged 5–9 was of the highest incidence in the analyzed database, followed by women aged 60–64. Incidence among female patients was higher than that among male patients in all age groups. [21] According to data on social trends, women are more likely to own a cat over men; [22] which supports higher incidence rates of this disease in women. Risk of contracting CSD increases as the number of cats residing in the home increases. [19] The number of pet cats in the United States is estimated to be 57 million. [20] Due to the large population of cats residing in the United States, the ability of this disease to continue to infect humans is vast. Laboratory diagnosis of CSD has improved in recent years, which may support an increase in incidence of the disease in future populations. [20]


Symptoms similar to CSD were first described by Henri Parinaud in 1889, and the clinical syndrome was first described in 1950 by Robert Debré. [23] [5] In 1983, the Warthin-Starry silver stain was used to discover a Gram-negative bacillus which was named Afipia felis in 1991 after it was successfully cultured and isolated. The causative organism of CSD was originally believed to be Afipia felis, but this was disproved by immunological studies in the 1990s demonstrating that cat-scratch fever patients developed antibodies to two other organisms, B. henselae (originally known as Rochalimea henselae before the genera Bartonella and Rochalimea were combined) and B. clarridgeiae, which is a rod-shaped Gram-negative bacterium. [5]

Related Research Articles

Trench fever is a moderately serious disease transmitted by body lice. It infected armies in Flanders, France, Poland, Galicia, Italy, Salonika, Macedonia, Mesopotamia, Russia and Egypt in World War I. Three noted sufferers during WWI were the authors J. R. R. Tolkien, A. A. Milne, and C. S. Lewis. From 1915 to 1918 between one-fifth and one-third of all British troops reported ill had trench fever while about one-fifth of ill German and Austrian troops had the disease. The disease persists among the homeless. Outbreaks have been documented, for example, in Seattle and Baltimore in the United States among injection drug users and in Marseille, France, and Burundi.

Carrions disease infectious disease produced by Bartonella bacilliformis infection

Oroya fever or Carrion's disease is an infectious disease produced by Bartonella bacilliformis infection.

Bartonellosis is an infectious disease produced by bacteria of the genus Bartonella. Bartonella species cause diseases such as Carrión´s disease, trench fever, cat-scratch disease, bacillary angiomatosis, peliosis hepatis, chronic bacteremia, endocarditis, chronic lymphadenopathy, and neurological disorders.


A bubo is defined as adenitis or inflammation of the lymph nodes and is an example of reactive lymphadenopathy.

Peliosis hepatis is an uncommon vascular condition characterised by multiple, randomly distributed, blood-filled cavities throughout the liver. The size of the cavities usually ranges between a few millimetres and 3 cm in diameter. In the past, it was a mere histological curiosity occasionally found at autopsies, but has been increasingly recognised with wide-ranging conditions from AIDS to the use of anabolic steroids. It also occasionally affects spleen, lymph nodes, lungs, kidneys, adrenal glands, bone marrow, and other parts of gastrointestinal tract.

Bartonella rochalimae is a recently discovered strain of Gram-negative bacteria in the genus Bartonella, isolated by researchers at the University of California, San Francisco (UCSF), Massachusetts General Hospital, and the United States Centers for Disease Control and Prevention. The bacterium is a close relative of Bartonella quintana, the microbe which caused trench fever in thousands of soldiers during World War I. Named after Brazilian scientist Henrique da Rocha Lima, B. rochalimae is also closely related to Bartonella henselae, a bacterium identified in the mid-1990s during the AIDS epidemic in San Francisco as the cause of cat scratch fever, which still infects more than 24,000 people in the United States each year.

Bartonella quintana, originally known as Rochalimaea quintana, and "Rickettsia quintana", is a micro-organism transmitted by the human body louse. This microorganism is the causative agent of the well known trench fever. This bacterium caused outbreaks of trench fever affecting 1 million soldiers in Europe during World War I.

Rickettsia felis is a species of bacterium, the pathogen that causes cat-flea typhus in humans. In cats the disease is known as flea-borne spotted fever. Rickettsia felis also is regarded as the causative organism of many cases of illnesses generally classed as fevers of unknown origin in humans in Africa.

Bartonella elizabethae, formerly known as Rochalimaea elizabethae, is a proteobacterium. Together with other Bartonella-species, it can cause disease in animals.

Afipia felis is the type species of the Afipia bacterial genus. It was formerly thought to cause cat-scratch disease. It is a Gram-negative, oxidase-positive, nonfermentative rod in the alpha-2 subgroup of the class Proteobacteria. It is motile by means of a single flagellum. It is noted for having the longest authority citation of any accepted species.

Bartonella koehlerae is a proteobacterium first isolated from cats. Its genome consists of 1.7-1.8 Mb.

Bartonella clarridgeiae is a Gram-negative bacteria from the genus of Bartonella which was first isolated in the United States. Bartonella clarridgeiae is a zoonotic pathogen which can cause cat scratch disease.

Cat bite The bite of the domestic cat

Cat bites are bites inflicted upon humans, other cats, and other animals by the domestic cat. Though uncommon, sometimes cat bites can lead to complications and, very rarely, death.

Human herpesvirus 8 associated multicentric Castleman disease is a subtype of Castleman disease, a group of rare lymphoproliferative disorders characterized by lymph node enlargement, characteristic features on microscopic analysis of enlarged lymph node tissue, and a range of symptoms and clinical findings.

Unicentric Castleman disease Localized Castleman disease (LCD) is the most common form of Castleman disease (CD; see this term) and it is usually asymptomatic or it may present with enlarged lymph nodes. LCD may be cured by surgical resection.

Unicentric Castleman disease is a subtype of Castleman disease, a group of lymphoproliferative disorders characterized by lymph node enlargement, characteristic features on microscopic analysis of enlarged lymph node tissue, and a range of symptoms and clinical findings

Idiopathic multicentric Castleman disease Castleman disease characterized by systemic inflammatory symptoms, polyclonal lymphoproliferation, cytopenias, and multiple organ system dysfunction caused by a cytokine storm often including interleukin-6

Idiopathic multicentric Castleman disease (iMCD) is a subtype of Castleman disease, a group of lymphoproliferative disorders characterized by lymph node enlargement, characteristic features on microscopic analysis of enlarged lymph node tissue, and a range of symptoms and clinical findings.


  1. Rapini, Ronald P.; Bolognia, Jean L.; Jorizzo, Joseph L. (2007). Dermatology: 2-Volume Set. St. Louis: Mosby. ISBN   1-4160-2999-0.[ page needed ]
  2. 1 2 3 4 5 6 7 8 9 "Cat scratch disease". GARD. Retrieved 2018-04-17.
  3. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 "Bartonellosis". NORD. 2017. Retrieved 30 September 2018.
  4. 1 2 3 4 5 6 7 8 9 10 Klotz SA, Ianas V, Elliott SP (2011). "Cat-scratch Disease". American Family Physician. 83 (2): 152–5. PMID   21243990.
  5. 1 2 3 4 5 6 7 8 9 10 11 Florin TA, Zaoutis TE, Zaoutis LB (2008). "Beyond cat scratch disease: widening spectrum of Bartonella henselae infection". Pediatrics. 121 (5): e1413–25. doi:10.1542/peds.2007-1897. PMID   18443019.
  6. Catscratch Disease~clinical at eMedicine
  7. Gajula V, Kamepalli R, Kalavakunta JK (2014). "A star in the eye: cat scratch neuroretinitis". Clinical Case Reports. 2 (1): 17. doi:10.1002/ccr3.43. PMC   4184768 . PMID   25356231.
  8. Perkocha LA, Geaghan SM, Yen TS, Nishimura SL, Chan SP, Garcia-Kennedy R, Honda G, Stoloff AC, Klein HZ, Goldman RL (1990). "Clinical and pathological features of bacillary peliosis hepatis in association with human immunodeficiency virus infection". The New England Journal of Medicine. 323 (23): 1581–6. doi:10.1056/NEJM199012063232302. PMID   2233946.
  9. Higgins JA, Radulovic S, Jaworski DC, Azad AF (1996). "Acquisition of the cat scratch disease agent Bartonella henselae by cat fleas (Siphonaptera:Pulicidae)". Journal of Medical Entomology. 33 (3): 490–5. doi:10.1093/jmedent/33.3.490. PMID   8667399.
  10. Foil L, Andress E, Freeland RL, Roy AF, Rutledge R, Triche PC, O'Reilly KL (1998). "Experimental infection of domestic cats with Bartonella henselae by inoculation of Ctenocephalides felis (Siphonaptera: Pulicidae) feces". Journal of Medical Entomology. 35 (5): 625–8. doi:10.1093/jmedent/35.5.625. PMID   9775583.
  11. Copeland, Claudia S. (2015). "Cat Scratch Fever? Really?: Cats, Fleas and the Many Faces of Bartonellosis". Healthcare Journal of Baton Rouge: 28–34. Archived from the original on 2015-11-22.
  12. Mascarelli PE, Maggi RG, Hopkins S, Mozayeni BR, Trull CL, Bradley JM, Hegarty BC, Breitschwerdt EB (2013). "Bartonella henselae infection in a family experiencing neurological and neurocognitive abnormalities after woodlouse hunter spider bites". Parasites & Vectors. 6: 98. doi:10.1186/1756-3305-6-98. PMC   3639822 . PMID   23587343.
  13. Lantos PM, Maggi RG, Ferguson B, Varkey J, Park LP, Breitschwerdt EB, Woods CW (2014). "Detection of Bartonella species in the blood of veterinarians and veterinary technicians: a newly recognized occupational hazard?". Vector Borne and Zoonotic Diseases. 14 (8): 563–70. doi:10.1089/vbz.2013.1512. PMC   4117269 . PMID   25072986.
  14. Rosado FG, Stratton CW, Mosse CA (2011). "Clinicopathologic correlation of epidemiologic and histopathologic features of pediatric bacterial lymphadenitis". Archives of Pathology & Laboratory Medicine. 135 (11): 1490–3. doi:10.5858/arpa.2010-0581-OA. PMID   22032579.
  15. Nelson, Christina A.; Saha, Shubhayu; Mead, Paul S. "Cat-Scratch Disease in the United States, 2005–2013". Emerging Infectious Diseases. 22 (10): 1741–1746. doi:10.3201/eid2210.160115. PMC   5038427 . PMID   27648778.
  16. Carithers, H. A. (1985-11-01). "Cat-scratch disease. An overview based on a study of 1,200 patients". American Journal of Diseases of Children. 139 (11): 1124–1133. doi:10.1001/archpedi.1985.02140130062031. ISSN   0002-922X. PMID   4061408.
  17. Rolain, J. M.; Brouqui, P.; Koehler, J. E.; Maguina, C.; Dolan, M. J.; Raoult, D. (2004-06-01). "Recommendations for Treatment of Human Infections Caused by Bartonella Species". Antimicrobial Agents and Chemotherapy. 48 (6): 1921–1933. doi:10.1128/AAC.48.6.1921-1933.2004. ISSN   0066-4804. PMC   415619 . PMID   15155180.
  18. Catscratch Disease~treatment at eMedicine
  19. 1 2 3 Chomel, Bruno B.; Boulouis, Henri J.; Breitschwerdt, Edward B. (April 15, 2004). "Cat scratch disease and other zoonotic Bartonella infections" (PDF). Vet Med Today: Zoonosis Update. 224: 1270–1279 via JAVMA.
  20. 1 2 3 4 5 Windsor, Jeffrey J. (2001). "Cat-scratch Disease: Epidemiology, Etiology, and Treatment" (PDF). British Journal of Biomedical Science. 58: 101–110.
  21. 1 2 3 4 5 Nelson, C. A., Saha, S., & Mead, P. S. (2016). Cat-Scratch Disease in the United States, 2005-2013. Emerging Infectious Diseases, 22(10), 1741-1746. doi:10.3201/eid2210.160115
  22. "Profile of Pet Owners". Pew Research Center. November 4, 2010. Retrieved November 29, 2017.
  23. Asano S (2012). "Granulomatous lymphadenitis". Journal of Clinical and Experimental Hematopathology. 52 (1): 1–16. doi:10.3960/jslrt.52.1. PMID   22706525.
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