From the Guidelines
Diagnosing Adult-Onset Still's Disease (AOSD) requires a comprehensive approach, focusing on clinical evaluation and laboratory tests, including fever, rash, musculoskeletal involvement, and high levels of inflammation, as outlined in the most recent EULAR/PRES recommendations 1. The diagnosis of AOSD typically begins with a thorough clinical evaluation, looking for the classic symptoms of high spiking fevers, salmon-pink rash, and arthritis or joint pain. According to the EULAR/PRES recommendations, operational definitions should be used to identify patients with Still's disease, including:
- Fever is typically spiking with temperature ≥39°C for at least 7 days
- Rash is transient and often coincides with fever spikes, preferentially involving trunk
- Musculoskeletal involvement is usually present with arthralgia/myalgia, and overt arthritis is supportive but not necessary for diagnosis
- High levels of inflammation are typically identified by neutrophilic leucocytosis, increased ESR, serum CRP, and ferritin 1. Laboratory tests are essential, including complete blood count, elevated inflammatory markers, and negative tests for rheumatoid factor and antinuclear antibodies. The Yamaguchi criteria are commonly used for diagnosis, which include major criteria (fever, arthralgia, rash, leukocytosis) and minor criteria (sore throat, lymphadenopathy, hepatosplenomegaly, abnormal liver function tests, negative RF and ANA) 1. It is also important to consider alternative diagnoses, such as malignancies, infectious diseases, and other immune-mediated inflammatory diseases, and to carefully evaluate the patient to exclude these conditions before initiating treatment for AOSD 1. Key biomarkers, such as serum IL-18 and S100 proteins, may also support the diagnosis of AOSD, although their use is currently limited to selected tertiary centers and requires further validation 1. The EULAR/PRES recommendations emphasize the importance of early diagnosis and treatment, and highlight the need for a comprehensive approach to diagnose AOSD, considering both clinical and biological findings 1.
From the Research
Diagnostic Criteria for Adult-Onset Still's Disease (AOSD)
The diagnostic criteria for AOSD are not well-established, but several studies have identified common symptoms and laboratory findings that can aid in diagnosis 2, 3, 4, 5, 6.
- Common symptoms of AOSD include:
- Spiking fever
- Maculopapular rash
- Arthralgia
- Sore throat
- Lymphadenopathy
- Serositis
- Splenomegaly
- Hepatomegaly
- Laboratory findings that may support a diagnosis of AOSD include:
- Elevated C-reactive protein
- Elevated ferritin levels
- Elevated erythrocyte sedimentation rate
- High levels of leukocytes with polymorphonuclear neutrophil count
- High platelet count
- The Yamaguchi criteria are often used to diagnose AOSD, which involves a set of clinical criteria and the exclusion of other diseases with similar symptomatology 6.
Challenges in Diagnosing AOSD
Diagnosing AOSD can be challenging due to its rarity and non-specific symptoms, which can mimic other diseases such as infection, autoimmune disease, and malignancy 3, 4, 5.
- A thorough medical history and detailed clinical examination are essential in the diagnostic process
- Laboratory and imaging tests are necessary to rule out alternative etiologies
- Early identification and initiation of treatment are critical to faster recovery and prevention of progression to severe complications 5