Hidradenitis Suppurativa (HS) is a chronic inflammatory skin condition characterized by painful, recurring lumps, abscesses, and tunnels, typically forming in the armpits, groin, and buttocks. While primarily affecting the skin, HS is recognized as a systemic inflammatory disorder. The body-wide inflammation associated with HS can manifest as various forms of inflammatory arthritis, meaning HS definitively causes joint pain. Managing HS often involves looking beyond the skin lesions to address potential joint complications.
Understanding the Link Between HS and Joint Pain
The connection between HS and joint pain stems from the underlying shared biological process: chronic systemic inflammation. HS is not merely a localized skin problem; the inflamed tissues in the skin lesions become a constant source of inflammatory molecules, known as cytokines. These molecules circulate throughout the bloodstream and can impact organs and tissues far removed from the skin, including the joints.
High levels of pro-inflammatory cytokines, such as Tumor Necrosis Factor-alpha (TNF-alpha), are implicated in the pathogenesis of HS. Since these same inflammatory mediators cause joint tissue damage in various forms of arthritis, their presence creates a biological link between the skin and joint symptoms. Treating this body-wide inflammation is necessary to control both the skin and joint manifestations of the disease.
Specific Types of HS-Associated Arthritis
People with HS have a significantly increased risk of developing inflammatory joint diseases. The most common joint conditions associated with HS fall under the umbrella of Spondyloarthritis, a group of inflammatory diseases that affect the spine and large joints. This includes Ankylosing Spondylitis (AS), which involves inflammation primarily in the spine and the sacroiliac joints.
HS is also strongly linked to Psoriatic Arthritis (PsA), a condition that causes joint pain, stiffness, and swelling. Both HS and PsA are classified as seronegative spondyloarthropathies, meaning they share similar inflammatory pathways but lack the rheumatoid factor found in Rheumatoid Arthritis (RA). While some studies observe an increased risk of RA in HS patients, the association with Spondyloarthritis is generally stronger.
The joint pain may occur in peripheral joints (knees, ankles, wrists) or be axial, affecting the lower back and buttock region. In some cases, joint pain appears just before or during an HS flare-up, suggesting a direct relationship between skin disease activity and joint symptoms. Less common complications include septic arthritis, a joint infection requiring immediate medical attention, or reactive arthritis.
Recognizing Inflammatory Joint Pain
Differentiating HS-related inflammatory joint pain from common mechanical pain, such as that caused by injury or osteoarthritis, is important for proper diagnosis. Mechanical pain typically worsens with activity and improves with rest, following a pattern of wear and tear. Inflammatory joint pain, however, is caused by the immune system mistakenly attacking joint tissue.
A hallmark sign of inflammatory pain is significant morning stiffness that lasts for a prolonged period, often exceeding 30 minutes to an hour. The pain often improves paradoxically with movement and exercise, and it can worsen after periods of inactivity or prolonged rest. Inflammatory pain frequently causes the patient to wake up during the second half of the night.
The pain is often chronic, persisting for more than three months, and can occur in younger individuals, typically under the age of 45. Swelling, warmth, and tenderness of the joints may also be present, which further suggests an inflammatory process. Sudden, severe joint swelling, especially when accompanied by fever, is a warning sign that requires urgent evaluation by a healthcare provider.
Treatment Strategies for Joint Symptoms
Treating the joint symptoms associated with HS often requires a multi-pronged approach that focuses on reducing the underlying systemic inflammation. Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) can be used for initial relief of pain and stiffness in the joints. However, for persistent or more severe inflammatory arthritis, systemic treatments are necessary.
Systemic therapies, particularly Biologics that target inflammatory proteins like TNF-alpha or Interleukin-17, are highly effective because they treat both the skin lesions and the arthritis simultaneously. Adalimumab, a TNF-alpha inhibitor, is approved for both moderate-to-severe HS and various forms of inflammatory arthritis, making it a common choice. Newer treatments, such as those targeting the IL-17 pathway, are also being used to calm the body-wide inflammation. Corticosteroids may be used for short-term management of acute flares to quickly reduce inflammation, but they are generally not suitable for long-term control.
Alongside medication, lifestyle modifications like maintaining a healthy weight and engaging in regular, low-impact exercise are beneficial for managing both HS and joint health. Due to the complex nature of inflammatory joint diseases, co-management with a rheumatologist is strongly recommended for anyone with HS who experiences persistent joint pain.