psoriatic arthritis

23 Jul

Psoriatic arthritis is a type of arthritis that affects the skin and nails. It causes joints to become swollen and painful- focusing on the distal interphalangeal joints. Nail pitting and Ankolysing spondylitis are associated with the condition. It can become progressively worse, similar to psoriasis.

- Psoriatic arthritis will affect 1.5 million Americans [1]
- According to NHS inform, between 20-40% of people with psoriasis will develop psoriatic arthritis [2]
- Between 2013-2015, North America and Europe found that 18-42% of people with psoriasis had arthritis as a secondary illness
- In Argentina, a study carried out in 2014 found that 17 out of 100 patients with psoriases has psoriatic arthritis [3]
- Inherited from family members
- Can be exacerbated by:
  - Infections
  - Accidents
  - Being overweight
  - Smoking
- Result of the immune system attacking healthy tissue [4,5]
Medical Students
- Genetic predisposition and HLA class I alleles (e.g. HLA-B27) are linked to psoriatic arthritis (PsA) and psoriasis.
- Environmental triggers (e.g. infections, trauma) activate chronic inflammation via the IL-23/IL-17 axis.
- Enthesitis (inflammation at entheses) is a hallmark of PsA, distinguishing it from synovitis in rheumatoid arthritis.
- The distal interphalangeal (DIP) joints are frequently affected due to high enthesis density and minimal synovial tissue.
- IL-23 activates resident T cells, which produce IL-17, IL-22, and TNF-α, leading to:
  - Inflammation
  - Osteoclast-mediated bone loss
  - Osteoblast-driven new bone formation (osteoproliferation)
- CD8+ T cells are key drivers of inflammation, supported by evidence of oligoclonal expansion in PsA.
- Additional immune contributors:
  - Th17 CD4+ cells, ILC3s, γδ T cells – all producing IL-17, IL-22, and TNF-α.
- Cytokines promote:
  - Neutrophil recruitment
  - Synoviocyte activation
  - Angiogenesis
  - Osteoclast and osteoblast activity
- Understanding this pathway has led to biologics targeting:
  - TNF, IL-17, IL-12/23, and IL-23, revolutionising treatment of PsA and psoriasis.
Patients
- Some people have genetic risks that make them more likely to develop psoriatic arthritis or psoriasis.
- Triggers like infections or stress to the joints can start long-term inflammation in both the skin and joints.
- Psoriatic arthritis commonly affects where tendons and ligaments attach to bones — this is called enthesitis.
- It often affects the finger joints, especially near the fingertips, because of how the joint is built.
- The body makes inflammatory proteins (like TNF and interleukins), which:
  - Cause pain, swelling, and joint stiffness.
  - Break down bone and cartilage.
  - Can also lead to new bone forming in the wrong places.
- Certain white blood cells, like T cells, play a big role in keeping the inflammation going.
- These immune reactions lead to damage inside the joints and also affect the skin.
- Treatments target these inflammatory proteins with medicines called biologics, like:
  - TNF inhibitors
  - IL-17 inhibitors
  - IL-23 inhibitors
- These medicines help reduce symptoms, prevent joint damage, and improve quality of life.
- History/current psoriasis diagnosis
- Inflammatory disorder of the nail unit (nail disease)
- Obesity
- Smoking
- Excessive alcohol consumption
- Environmental triggers such as trauma, stress, infection [7]
- Joint involvement of the fingers- including enlargement (swelling) of the joints with inflammation
- Sausage shaped deformities (dactylitis)
- Nail pitting
- Inflammation of areas where the bone attaches to the tendon, known as enthesopathy (eg. Achilles tendonitis (inflammation of the Achilles tendon)
- In Ankolysing Spondylitis, psoriatic arthritis may involve the sacral and iliac joints (found in the lower back) in its impact [8]
- Clinical examination of the joints and fingers that show a sausage shape appearance
- Blood tests to rule out rheumatoid arthritis (including rheumatoid factor and anti-cyclic citrullinated peptide antibody)- if they are positive, can suspect rheumatoid arthritis
- X-ray screening can be used to determine whether treatment contributes to further damage/ progression of damage
- Nail examination to assess ridges, pitting or abnormal growth of the nail away from the nail bed [1]
- Rheumatoid arthritis- another form of arthritis causing inflammation
- Reactive arthritis- triggered due to infections causing arthritic symptoms
- Ankylosing spondylitis (involvement of the lower back in symptoms) [9]
Medical Students
- Control inflammation and pain.
- Prevent joint and skin damage.
- Induce remission or slow disease progression.
- Maintain joint function and quality of life.
Pharmacological Treatments
- NSAIDs (e.g. ibuprofen, naproxen): First-line for mild disease.
- Biologic DMARDs:
  - TNF inhibitors (e.g. adalimumab, etanercept, infliximab) are first-line for moderate-to-severe PsA.
  - IL-17 inhibitors and IL-12/23 inhibitors for TNF-refractory cases.
  - Abatacept: An alternative biologic for inadequate response or intolerance.
  - Only one biologic is prescribed at a time.
- Conventional DMARDs: e.g. methotrexate—modulates immune response to reduce joint and skin damage.
- Targeted synthetic DMARDs: Selectively inhibit immune pathways (e.g. JAK inhibitors).
- Corticosteroids:
  - Intra-articular injections for acute flares.
  - Short-term use only.
Topical Therapies for Skin Psoriasis
- Topical corticosteroids, vitamin A analogues, coal tar, anthralin, and salicylic acid may be used adjunctively.
Non-Pharmacological Management
- Physical therapy and regular exercise to improve joint mobility and reduce stiffness.
- Avoid chlorinated pools during flares due to skin irritation.
- Encourage weight loss in patients with obesity to improve treatment response.
- Promote smoking cessation and stress management.
Lifestyle and Diet
- Recommend Mediterranean-style diet: rich in fatty fish, olive oil, nuts, fruits, and vegetables.
- Avoid pro-inflammatory foods: red meat, processed foods, high-fat and high-sugar diets.
Other Supportive Therapies
- Acupuncture, moist heat or ice therapy, rest during flares.
- Paraffin baths for small joints (hands and feet).
Patients
Goals of Treatment
- Slow the condition and try to stop it from getting worse.
- Ease pain, swelling, and stiffness.
- Protect your joints and skin.
Medication Options
- Pain relievers: Like ibuprofen or naproxen for mild cases.
- Biologic medicines: Usually the first strong option—these calm the immune system and help protect your joints and skin.
- Methotrexate and other drugs: Help slow joint damage and inflammation.
- Steroid injections: Can quickly reduce pain and swelling during a flare-up.
- Creams and ointments: Help manage psoriasis on your skin (e.g. coal tar, salicylic acid, vitamin A creams).
Stay Active
- Exercise helps reduce stiffness, boost energy, and protect your joints.
- Don’t swim during flare-ups if chlorine irritates your skin.
- Rest when you need to but keep moving when you feel better.
Eat Well
- Try a Mediterranean diet: fish (like salmon or tuna), olive oil, nuts, fruits, and vegetables.
- Avoid red meat, junk food, and sugary snacks, which can increase inflammation.
- Losing weight if you're overweight can make treatments work better.
Other Tips
- Stop smoking and reduce stress it helps your body respond better to treatment.
- Heat and cold: Warm baths or heat packs can soothe sore joints. Cold packs reduce swelling. Use whichever feels best.
- Alternative therapies like acupuncture may help some people. [8]
- Arthritis mutilans- severe, painful form of psoriatic arthritis which can lead to deformity [10]
- Having psoriasis automatically means you will have psoriatic arthritis
- Psoriatic arthritis doesn’t flare up
- There is only one type of psoriatic arthritis
- Psoriatic arthritis will always become severe as time continues [11]
- What caused by psoriatic arthritis?
- How can I check for signs of a flare up?
- What type of psoriatic arthritis do I have?
- What lifestyle changes can I make to help my symptoms?
- How long will treatment take to be effective?
- Who do I contact if I start experiencing complications?
- Psoriasis and Psoriatic Arthritis Alliance
- Arthritis Foundation
- SELF.com
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