HS and
Rheumatoid Arthritis
Both HS and rheumatoid arthritis are driven by the same dysregulated immune pathways. Understanding this connection can unlock better treatment options for patients living with both conditions.
HS Is a Systemic Inflammatory Disease
HS is not just a skin condition. The same dysregulated immune pathways that cause painful nodules and abscesses in the skin also drive systemic inflammation that can affect the joints, cardiovascular system, and metabolism. Rheumatoid arthritis and HS share key inflammatory mediators - including TNF-alpha and IL-17 - which is why some biologic treatments are effective for both conditions.
Why HS and RA Are Linked
HS and rheumatoid arthritis share four key inflammatory mechanisms that explain their co-occurrence and their response to similar treatments.
TNF-alpha Overproduction
Tumor necrosis factor-alpha (TNF-α) is a master pro-inflammatory cytokine that is significantly elevated in both HS and RA. In HS, TNF-α drives the formation of painful nodules and abscesses in the skin. In RA, it promotes synovial inflammation and progressive joint destruction. This shared pathway is why TNF-alpha inhibitors such as adalimumab (Humira) and infliximab are effective in both conditions.
IL-17 Pathway Dysregulation
Interleukin-17 (IL-17) is a cytokine that plays a central role in both HS and several forms of inflammatory arthritis, including RA and ankylosing spondylitis. Elevated IL-17 promotes neutrophil recruitment and tissue destruction. IL-17 inhibitors (secukinumab, ixekizumab) are approved for RA-related conditions and are currently being evaluated in HS clinical trials.
Innate Immune Dysregulation
Both HS and RA involve dysregulation of the innate immune system - the body's first line of defense. In HS, this manifests as inappropriate activation of the inflammasome (particularly NLRP3) and toll-like receptors in the skin. In RA, similar innate immune activation drives synovial inflammation. This shared root cause explains why both conditions respond to immunomodulatory therapies.
Chronic Systemic Inflammation
Both HS and RA are systemic inflammatory diseases - they are not confined to the skin or joints. Elevated inflammatory markers (CRP, ESR, IL-6) are found in both conditions. This systemic burden increases the risk of cardiovascular disease, metabolic syndrome, and depression in patients with either or both conditions. Treating one disease effectively may reduce the overall inflammatory load and benefit the other.
Biologics That Work for Both HS and RA
Several biologic medications target the shared inflammatory pathways in HS and RA. Patients with both conditions may benefit from a single biologic that addresses both diseases.
| Biologic | Mechanism | HS Approved | RA Approved | Notes |
|---|---|---|---|---|
| Adalimumab (Humira) | TNF-α inhibitor | The only biologic FDA-approved for both HS and RA. First-line biologic for moderate-to-severe HS. | ||
| Infliximab (Remicade) | TNF-α inhibitor | - | Approved for RA; used off-label for HS with evidence of benefit, particularly in severe or refractory cases. | |
| Etanercept (Enbrel) | TNF-α inhibitor | - | Approved for RA; limited evidence in HS. Some case reports suggest benefit but controlled trial data is lacking. | |
| Secukinumab (Cosentyx) | IL-17A inhibitor | - | - | Approved for ankylosing spondylitis and psoriatic arthritis; under active investigation in HS Phase 3 trials. |
| Bimekizumab (Bimzelx) | IL-17A/F inhibitor | - | FDA-approved for HS (2023). Dual IL-17A/F blockade. Being studied in RA-related conditions. | |
| Upadacitinib (Rinvoq) | JAK1 inhibitor | - | Approved for RA; in Phase 3 trials for HS. JAK inhibitors represent a promising next-generation option for both conditions. |
Approval status as of 2024. Always discuss treatment options with your dermatologist and rheumatologist.
Warning Signs of RA in HS Patients
Joint pain and fatigue are common in HS patients due to systemic inflammation, but some symptoms specifically suggest rheumatoid arthritis and warrant a rheumatology evaluation. If you experience any of the following alongside your HS, speak to your doctor.
- Morning joint stiffness lasting more than 30 minutes
- Symmetrical joint swelling (same joints on both sides of the body)
- Tender, warm, or swollen joints - especially in hands, wrists, and feet
- Fatigue disproportionate to your level of activity
- Joint pain that improves with movement but worsens with rest
- Rheumatoid nodules (firm lumps under the skin near joints)
- Elevated CRP or ESR on blood tests
- Positive rheumatoid factor (RF) or anti-CCP antibody test
Coordinating Your Care
If you have both HS and RA (or suspect you might), coordinating care between your dermatologist and rheumatologist is essential. Key discussion points include:
- Whether a single biologic (e.g., adalimumab) can treat both conditions
- How to monitor for cardiovascular risk, which is elevated in both diseases
- Whether methotrexate (common in RA) is appropriate given your HS severity
- Infection screening before starting biologics (required for both conditions)
What to Tell Your Rheumatologist
Many rheumatologists are not familiar with HS. When you see a rheumatologist, bring this information:
- Your HS diagnosis, Hurley stage, and affected body areas
- Current and past HS treatments (especially biologics)
- A timeline of when joint symptoms began relative to HS onset
- Any family history of RA, psoriatic arthritis, or ankylosing spondylitis
Common Questions
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