What is Acute Rheumatic Fever? Fact Checked
Acute rheumatic fever (ARF) is an illness following an autoimmune response to a group A streptococcus, or ‘Strep A’ infection. Strep A bacteria can cause infection in various parts of the body, including the throat (strep throat) and skin (skin sores, pyoderma, impetigo). Strep A skin infection can occur on healthy skin, but is commonly seen as a complication of scabies infection. Strep A is associated with up to 37% of sore throats1, and up to 82% of impetigo skin infections.2,3 For some people with these Strep A infections, the body’s immune system gets confused when reacting to the throat or skin infection, and the result is a generalised inflammatory illness called acute rheumatic fever.
What are the symptoms of acute rheumatic fever?4
- Arthritis: one or more joints may be red, hot, painful, swollen; mainly the larger joints like the knees, ankles, wrists and elbows. (very common)
- Fever: hot and cold chills which may feel like symptoms of a cold or flu. (very common)
- Sydenham chorea: jerky, uncoordinated, uncontrollable movements, particularly of the hands, legs, tongue and face. (uncommon)
- Carditis: swelling of the heart and the heart valves. (this may or may not be obvious)
- Erythema marginatum: a painless skin rash, usually on the trunk of the body, sometimes on the arms and legs, almost never on the face. (rare)
- Subcutaneous nodules: small, round, painless lumps over the elbows, wrists, knees, ankles and areas near the spine. (rare)
The severity of the ARF illness can range from very mild, with few of the above symptoms, to severe where the person may be bed-bound due to join pain or heart failure. All people with ARF, regardless of severity, should be admitted to hospital.4 ARF can be difficult to diagnose because different people experience different symptoms; the different symptoms do not all occur together, and symptoms may be subtle or may be confused with other conditions.5,6 Despite the seriousness of the illness, ARF typically leaves no lasting damage to the brain, joints or skin. However, if the heart is involved (acute carditis), damage to the heart valves may remain once the acute carditis has resolved. This lasting heart valve damage is known as rheumatic heart disease (RHD).
Recurrent Strep A infections and episodes of ARF can cause further damage to the heart valves, making RHD progressively worse over time. More than half of the people with ARF will develop RHD with 10 years.7
Regular antibiotics are prescribed for people who have had ARF, usually for many years, to prevent future Strep A infections, recurrent ARF, and subsequent development or worsening of RHD.4
Who is at risk?
There are several population groups in Australia at high risk of ARF.4
- Aboriginal and Torres Strait Islander peoples, particularly those living in rural or remote settings across central and northern Australia, are known to be at very high risk.
- Aboriginal and Torres Strait Islander peoples, and Māori and Pacific Islander groups living in urban settings, particularly where there is household crowding, are also at high risk.
- People with a history of ARF or RHD are at high risk of recurrent ARF.
A person’s risk of ARF is thought to be based on several factors:
- Environmental conditions associated with exposure to high levels of streptococcal bacteria, particularly overcrowded housing. Strep A bacteria are spread through sneezing or coughing (if the infected person has Strep A in the throat) or direct skin contact (if the infected person has Strep A skin sores) so it is easily transmitted from one person to another in close living conditions.
- Children who experience multiple Strep A infections are at highest risk for developing the abnormal immune response which triggers ARF.
- There is some genetic susceptibility to ARF, but the link is relatively weak compared with the importance of shared environmental risk factors.9 It is not uncommon for more than one person in a family to have had ARF chiefly due to shared environmental exposures.
- Only some strains of group A streptococcus are rheumatogenic. This means that some types (strains) of streptococcal bacteria are more likely associated with ARF than others. Therefore, not all people who have a Strep A infection will develop ARF, either because the Strep A strain is not rheumatogenic, and/or because their immune system does not generate the ARF response.
- Shaikh N, Leonard E, Martin JM. Prevalence of streptococcal pharyngitis and streptococcal carriage in children: a meta-analysis. Pediatrics. 2010;126(3):e557-e564.
- McDonald M, Towers RJ, Andrews RM, et al. Low rates of streptococcal pharyngitis and high rates of pyoderma in Australian Aboriginal communities where acute rheumatic fever is hyperendemic. Clinical Infectious Diseases. 2006;43(6):683-689.
- Carapetis J, Connors C, Yarmirr D, et al. Success of a scabies control program in an Australian Aboriginal community. The Pediatric Infectious Disease Journal. 1997;16:494-499.
- RHDAustralia (ARF/RHD writing group). The 2020 Australian guideline for prevention, diagnosis and management of acute rheumatic fever and rheumatic heart disease (3rd edition). 2020
- Ralph A, Jacups S, McGough K, et al. The challenge of acute rheumatic fever diagnosis in a high-incidence population: a prospective study and proposed guidelines for diagnosis in Australia’s Northern Territory. Heart Lung and Circulation. 2006;15(2):113-118.
- Cann M, Sive AA, Norton RE, et al. Clinical presentation of rheumatic fever in an endemic area. Archives of Disease in Childhood. 2010;95(6):455-457.
- He VYF, Condon JR, Ralph AP, et al. Long-term outcomes from acute rheumatic fever and rheumatic heart disease: A data-linkage and survival analysis approach. Circulation. 2016;134:222-232.
- Australian Institute of Health and Welfare 2019. Acute rheumatic fever and rheumatic heart disease in Australia. Cat. no: CVD 86. Canberra.
- Gray LA, D'Antoine HA, Tong SYC, et al. Genome‐wide analysis of genetic risk factors for rheumatic heart disease in Aboriginal Australians provides support for pathogenic molecular mimicry. Journal of Infectious Diseases. 2017;216:1460-1470.