The acutely swollen joint

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  • See also

    The limping or non-weight bearing child

    Bone and Joint infection


    Henoch-Schönlein purpura

    Serum Sickness and Serum Sickness Like Reactions (SSLRs)

    Key points

    1. There are many causes of an acutely swollen joint. The aim of initial assessment is to identify and treat serious ones
    2. Acute inability to walk or weight bear is a red flag
    3. Septic arthritis is an orthopaedic emergency and should be suspected in any child presenting with localised severe joint pain and swelling, especially with fever
    4. Children discharged with an unclear diagnosis require early follow up


    • Joint swelling is a common feature in many conditions that affect children
    • History, examination, and tailored investigations will help to differentiate serious from benign causes
    • In a child who is limping or non-weight bearing without a swollen joint please see The limping or non-weight bearing child



    • Joint swelling: site, onset (<2 weeks is acute), character (migratory/early morning)
    • Fever
    • Functional limitation eg refusal to weight bear, or use affected joint
    • Constant severe pain or night pain
    • Trauma/injury
    • Systemic features: Weight loss/fatigue/night sweats, rash, unexplained bruising, visual impairment, diarrhoea
    • Recent illness
    • Family history: haemophilia, autoimmune or inflammatory conditions
    • Medication
    • At risk sexual behaviour/intravenous drug use
    • Groups at risk for acute rheumatic fever (ARF): Indigenous Australians, Maori and Pacific Islanders; personal or family history of ARF or rheumatic heart disease


    • Fever
    • Joint and limb assessment using the “Look, feel, move”, start with non-painful side
      • Look: bruising/erythema/muscle wasting
      • Feel: warmth, tenderness, also palpate tendons (enthesitis), and muscles and contiguous limbs
      • Move: caution if severe pain
        • active: facilitate by placing toy or parent out of reach
        • passive: assess for limitations and asymmetry
      • General musculoskeletal/functional/neurological and gait assessment
    • Haematological: Pallor, lymphadenopathy, petechiae/ecchymosis/purpura
    • Abdominal: Hepatosplenomegaly, abdominal mass
    • Skin: Rash/ bruising/hyperextensibility
    • Cardiac: cardiomegaly, thrill, pericardial rub, murmur
    • Eye: Red eye, decreased visual acuity, restriction in extraocular movement

    Common differential diagnoses



    Clinical features


    Septic arthritis/ Osteomyelitis

    Severe localised joint and/or limb pain
    Systemic features, fever (acute onset)
    Commonly lower limb joints

    Viral arthritis eg Enterovirus/Hepatitis B/Parvovirus/ Dengue

    Cough, fever, rash
    At risk sexual/drug taking behaviour
    High risk contact of identified case
    Travel history to endemic area


    Fracture/dislocation/soft tissue injury

    History of injury

    Child abuse

    Unexplained injury, bruising
    Particularly if non ambulatory child


    Reactive arthritis

    Recent illness: pharyngitis, gastroenteritis, urethritis (Chlamydia)
    Onset 7 to 14 days later
    Oligo/monoarticular arthritis, normally lower limbs



    Personal/Family history
    Unexplained bruising/bleeding
    Most commonly knee


    Juvenile idiopathic arthritis/mixed connective tissue disease

    Fever, rash
    Oligo/polyarticular arthritis
    Normally can weight bear

    Other systemic inflammatory disorders

    Kawasaki disease


    Prolonged fever >5 days
    Rash, conjunctivitis, cervical lymphadenopathy, swelling of hands and feet

    Acute rhematic fever (ARF)

    At risk population
    Migratory polyarthritis/arthralgia – usually large joints
    Heart murmur (mitral or aortic regurgitation)
    Skin changes (erythema marginatum/subcutaneous nodules) – seen rarely


    Henoch-Schönlein purpura

    Purpuric rash (normally affecting lower limbs)
    Usually lower limb joints affected
    Preceding upper respiratory joint infection


    Serum sickness/ Serum sickness like reactions

    Recent medication use
    Urticarial type rash, but can also present with papular or purpuric rash


    Bone/soft tissue malignancy/
    Solid organ tumour

    Fever, weight loss, lethargy, fatigue, anorexia, night sweats,

    Nocturnal pain
    Pallor, bruising
    Hepatosplenomegaly/abdominal mass



    Maternal vitamin D deficiency
    At risk for vitamin D deficiency (poor sunlight exposure/dark skin, predisposing medical conditions)
    Genu varum/valgus, widened wrists/ankles

    Inflammatory bowel disease

    Ulcerative colitis
    Crohn’s disease

    Fever, diarrhoea, weight loss, uveitis, abdominal pain


    Ehlers-Danlos, other 

    Repetitive injury, recurrent subluxation/dislocation
    Fatigue, chronic pain
    Easy bruising/scarring of skin
    Joint laxity, hyperextensible skin



    • Consider no investigations if:
      • No red flags
      • A clear working diagnosis and/or a plan to review within 7 days
    • Investigations will be guided by the clinical features – with suggestions summarised in the flow chart below

    Suggested diagnostic approach to acute joint swelling based on clinical features


    • Definitive management is determined by the working diagnosis
    • Pain management: see acute pain management and consider immobilization
    • Child-directed limitation of activity
    • Septic arthritis is an orthopaedic emergency - consult local orthopaedic team
    • For infective causes, refer to the appropriate sub-specialist team and consult  local antibiotic guidelines
    • Acute rheumatic fever:
      • All suspected cases should be discussed with a paediatrician experienced in ARF, ID physician or paediatric cardiologist
      • An echocardiogram is required even if no clinical murmur to exclude subclinical carditis
      • Avoid NSAIDS during diagnostic workup, as these may mask migratory joint symptoms

    Consider consultation with local paediatric team when

    Refer for specialist assessment if:

    • Suspected septic arthritis (orthopaedics)
    • Suspected haemarthrosis in a known or suspected haemophiliac (haematology)
    • Joint pain >4 weeks and/or multiple joints involved, or vasculitis other than HSP (rheumatology)

    Consider transfer when

    The child requires care above the level of comfort of the local hospital

    For advice about acutely unwell transfers requiring PICU or neonatal retrievals see Retrieval Services

    Consider discharge when

    • The cause of the swollen joint has been identified and appropriately managed
    • If the diagnosis is unclear:
      • The child’s pain is adequately managed AND
      • High risk diagnoses have been considered and excluded AND
      • Appropriate follow up has been arranged

    Parent information

    Pain relief for children - paracetamol and ibuprofen

    Last updated October 2021

  • Reference List

    1. Balan S. Approach to Joint Pain in Children. Indian Journal of Pediatrics. 2016;83(2):135-139. doi:10.1007/s12098-015-2016-8
    2. Kimura Y, Southwood TR. Evaluation of the child with joint pain and/or swelling. UpToDate. (Accessed February 21, 2021).
    3. Nannery R, Heinz P. Approach to Joint Pain in Children. Paediatric and Child Health. 2018 Feb;28(2):43-49.
    4. 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
    5. Vardiabasis NV, Schlechter JA. Definitive Diagnosis of Children Presenting to A Pediatric Emergency Department With Fever and Extremity Pain. J Emerg Med. 2017 Sep;53(3):306-312. doi: 10.1016/j.jemermed.2017.05.030. PMID: 28992868.
    6. Starship Hospital Guidelines. Limp – assessment of paediatric limp in the Emergency Department. Published 25 August 2020.