Adult-Onset Still's Disease (AOSD) is a rare and systemic inflammatory disorder that primarily affects adults, typically manifesting with high fevers, a salmon-colored rash, joint pain, and a variety of other symptoms. It is considered an autoinflammatory disease, which means the body's immune system malfunctions and triggers inflammation without the presence of infection or a specific autoimmune cause. AOSD can be difficult to diagnose because its symptoms overlap with those of several other conditions, including infections, other forms of arthritis, and autoimmune diseases like rheumatoid arthritis.
What is Adult-Onset Still's Disease?
AOSD is part of a group of disorders known as systemic inflammatory diseases. The exact cause of the disease remains unknown, but it is believed that a combination of genetic, environmental, and immune system factors contribute to its onset. Unlike autoimmune diseases, where the immune system mistakenly attacks the body’s tissues, autoinflammatory diseases like AOSD are characterized by inappropriate activation of the immune system that results in inflammation.
AOSD is a disease that affects multiple organ systems, including the joints, skin, and internal organs. While it can occur at any age, it most commonly appears in young adults, typically between the ages of 16 and 35, although it can be diagnosed in older individuals as well.
Symptoms of Adult-Onset Still's Disease
The symptoms of AOSD can vary greatly from person to person, and their severity can fluctuate over time. Common symptoms include:
High Spiking Fevers: A hallmark of AOSD is the presence of intermittent, high spiking fevers, often reaching up to 104°F (40°C), which typically occur in the late afternoon or evening. These fever episodes are usually followed by a period of normal body temperature.
Salmon-Colored Rash: Another classic symptom of AOSD is a distinctive, salmon-colored rash that typically appears during fever spikes. This rash is usually non-itchy and can appear on the trunk, limbs, or upper arms. It often fades once the fever subsides.
Arthritis and Joint Pain: Joint involvement is a common feature of AOSD, with inflammation often affecting the larger joints like the knees, wrists, and ankles. The arthritis can be either intermittent or persistent and is often accompanied by severe pain and swelling.
Muscle Pain and Fatigue: Along with joint pain, patients frequently experience generalized muscle pain (myalgia) and chronic fatigue. These symptoms can be debilitating and affect daily functioning.
Enlarged Lymph Nodes and Spleen: Many individuals with AOSD have swollen lymph nodes (lymphadenopathy) and an enlarged spleen (splenomegaly), which may contribute to discomfort and general malaise.
Sore Throat: Some individuals may experience a sore throat or inflammation in the throat area, which can be part of the systemic inflammation occurring in the body.
Liver Involvement: In some cases, the liver may become inflamed (hepatitis), leading to symptoms such as jaundice or elevated liver enzymes.
These symptoms often come in "attacks" or flare-ups, with periods of remission in between. However, the severity and frequency of these flare-ups can vary greatly.
Diagnosis of Adult-Onset Still's Disease
Diagnosing AOSD can be challenging due to its nonspecific symptoms, which can mimic other conditions, such as viral infections, lymphoma, or other autoimmune diseases. There is no single test to confirm AOSD, so a diagnosis is typically made based on a combination of clinical symptoms and lab tests.
Blood Tests: Blood tests may show elevated levels of inflammatory markers such as C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR). These are common in many inflammatory conditions but not exclusive to AOSD. An elevated white blood cell count (leukocytosis) is also commonly seen.
Fever Pattern: The characteristic fever pattern in AOSD—daily spikes, often in the late afternoon or evening—is a key diagnostic feature that can help distinguish AOSD from other conditions.
Exclusion of Other Conditions: Because AOSD can resemble other diseases, including infections and malignancies, a thorough medical history, physical examination, and various imaging tests are essential to rule out other potential causes.
Diagnostic Criteria: In 1992, the Yamaguchi criteria were developed as a tool for diagnosing AOSD. This set of criteria includes specific symptoms such as the characteristic rash, fever, and joint involvement, and requires the exclusion of other diseases.
Treatment of Adult-Onset Still's Disease
While there is no cure for AOSD, the goal of treatment is to manage symptoms, control inflammation, and improve quality of life. Treatment typically involves medications to reduce inflammation, control pain, and prevent damage to the joints and other organs.
Nonsteroidal Anti-Inflammatory Drugs (NSAIDs): These are often used to reduce fever and inflammation. Drugs like ibuprofen or naproxen can help manage pain and decrease inflammation.
Corticosteroids: For more severe symptoms, corticosteroids such as prednisone may be prescribed. Steroids help reduce inflammation and control the immune system’s overactivity. However, long-term use of steroids can have side effects, including weight gain, osteoporosis, and increased risk of infection.
Disease-Modifying Antirheumatic Drugs (DMARDs): In cases where NSAIDs and steroids are insufficient, DMARDs like methotrexate or sulfasalazine may be used to slow down the disease process and manage joint involvement.
Biologic Agents: For patients with severe or refractory AOSD, biologic drugs such as anakinra, an interleukin-1 (IL-1) receptor antagonist, or tocilizumab, an IL-6 receptor antagonist, may be used to target specific immune pathways involved in the disease. These drugs have shown promise in controlling disease activity and preventing flare-ups.
Supportive Care: Managing fatigue and joint pain with physical therapy, rest, and a balanced diet can help improve quality of life for individuals with AOSD. Psychological support may also be beneficial to cope with the emotional toll the disease can take.
Prognosis
The prognosis of AOSD varies significantly from person to person. Some people experience only mild symptoms and go into remission after a few months or years, while others may have chronic, long-lasting symptoms and complications. In severe cases, AOSD can lead to organ damage, particularly to the heart, lungs, or liver.
With proper treatment, many individuals with AOSD can manage their symptoms and lead relatively normal lives. Early diagnosis and prompt treatment are crucial in preventing long-term complications and improving outcomes.
Conclusion
Adult-Onset Still's Disease is a rare and complex inflammatory disorder that can cause significant pain, discomfort, and life disruptions for those affected. While its cause remains unclear, advances in medical treatments, including biologic agents, have improved the outlook for many individuals with AOSD. Awareness of the symptoms and early intervention are key to managing the disease and preventing severe complications. With the right approach, individuals with AOSD can find relief from the symptoms and achieve better long-term health outcomes.
References
Fautrel, B., Zirkzee, E. J., & Lelièvre, T. (2018). Adult-onset Still’s disease: State of the art and future perspectives. Autoimmunity Reviews, 17(7), 714-723. https://doi.org/10.1016/j.autrev.2018.02.015
Goswami, R., & Smith, R. (2020). Diagnosis and management of Adult-Onset Still’s Disease: A review. Journal of Clinical Rheumatology, 26(4), 184-191. https://doi.org/10.1097/RHU.0000000000001312
Leipe, J., & Landmann, F. (2020). A comprehensive review of Adult-Onset Still's disease: Pathogenesis, clinical features, and treatment strategies. Rheumatology International, 40(7), 1021-1029. https://doi.org/10.1007/s00296-020-04614-2
Yamaguchi, M., Ohta, A., & Tsunematsu, T. (1992). Preliminary criteria for the classification of adult-onset Still’s disease. The Journal of Rheumatology, 19(3), 424–430. https://www.jrheum.org/content/19/3/424
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