Psoriasis does not only affect the skin. For some people, the same problem also affects the joints. This is called psoriatic arthritis.
What is psoriatic arthritis?
In psoriasis, your immune system (your body's defence team) attacks healthy skin, causing raised patches. These look pink or red on white skin, and grey on brown or black skin, sometimes leaving dark marks behind (NHS, 2026).
In psoriatic arthritis, it also attacks the joints and the places where tendons attach to bone, causing pain, swelling and stiffness (Arthritis UK, no date a; NHS, 2023). Starting treatment early gives the best chance of keeping it under control (Arthritis UK, no date a).
Signs to look out for
| Sign | What you might notice |
|---|---|
| Stiff, painful joints | Worse when you get up after resting, lasting more than 30 minutes |
| "Sausage" fingers or toes | A whole finger or toe swells up |
| Tender spots | Soreness where tendons join bone, such as the back of the heel |
| Nail changes | Small dents, colour changes or thickening of the nails |
| Tiredness | Severe, ongoing tiredness that does not get better with rest |
Source: Arthritis UK (no date a); NHS (2023).
From plaque psoriasis to psoriatic arthritis: how it happens
About 1 in 4 people with psoriasis go on to develop psoriatic arthritis. It most often appears within 10 years of psoriasis starting, but it can begin at any age. For some people, joint pain comes before any skin patches, and even mild psoriasis can lead to it (Psoriasis UK, no date).
Nobody knows exactly why some people develop it (NHS, 2023). It seems to be a mix of genes and a trigger, such as an infection or injury (Arthritis UK, no date a).
Who is more likely to develop it?
A review of the research found that where your psoriasis shows up matters (Rouzaud et al., 2014):
| Where your psoriasis is | Chance of psoriatic arthritis |
|---|---|
| Nails | Nearly 3 times higher |
| Scalp | Nearly 4 times higher* |
| Buttock crease or around the bottom | More than 2 times higher* |
| 3 or more areas of the body | More than 2 times higher* |
*Figure from a single study, so treat it as a rough guide.
Carrying extra weight and smoking also raise the chances (Arthritis UK, no date a). Read more about nail psoriasis.
How plaque psoriasis can lead to psoriatic arthritis.
When another health condition is in the mix: living with HIV
You might expect HIV, which weakens part of the immune system, to calm psoriasis down. Often the opposite happens: psoriasis tends to be more severe and longer-lasting (Ceccarelli et al., 2019).
HIV is also linked with more psoriasis and psoriatic arthritis. A Canadian study of over 20,000 people found those living with HIV were about 1.7 times more likely to be diagnosed with either (Damba et al., 2021). In sub-Saharan Africa, psoriatic arthritis is seen mainly in people with HIV (Tikly, Njobvu and McGill, 2014).
However, research has not yet shown whether people with HIV and psoriasis are more likely to go on to develop arthritis. A Thai study even found lower rates among people with HIV (Chaiyabutr et al., 2022).
Modern HIV treatment has improved both conditions for many people, but immune-calming arthritis medicines have been little studied in people with HIV (Ceccarelli et al., 2019). Keep your HIV and rheumatology teams in the loop.
Fair care for everyone
Most psoriatic arthritis research has involved white people, though symptoms may differ across ethnic groups (Haberman et al., 2025). In the US, Black patients waited longer to start key treatments than white patients (Patel et al., 2023). If you feel your symptoms are being missed, ask for a second opinion.
Looking after your mind
Psoriasis and psoriatic arthritis can both take a toll on your mental health (Arthritis UK, no date a; NHS, 2026). If this happens, ask about a referral for support.
Getting checked
NICE says everyone with psoriasis should be offered a yearly check for psoriatic arthritis, especially in the first 10 years. This often uses a short questionnaire. If arthritis is suspected, you should be referred to a rheumatologist, a joint specialist (NICE, 2012).
How it is treated
| Treatment | What it does |
|---|---|
| Anti-inflammatory painkillers (tablets, creams or gels) | Help with mild symptoms |
| Steroid injections | Injected into a joint to ease pain |
| Medicines that calm the immune system, such as methotrexate | Used for moderate to severe symptoms; can take several months to work |
| Biological medicines | Usually injections; used if the medicines above do not help |
| Physiotherapy and occupational therapy | Exercises to strengthen your joints, plus changes at home and work |
Source: NHS (2023); Arthritis UK (no date a).
Help and support
- Arthritis UK: read the free psoriatic arthritis booklet (Arthritis UK, no date b), try their free exercise programmes (Arthritis UK, no date c), or call the free helpline on 0800 5200 520, Monday to Friday, 9am to 6pm.
- Money: Personal Independence Payment (PIP) helps with extra costs of a long-term condition, even if you work (GOV.UK, no date b).
- Work: Access to Work can pay for equipment or support at work (GOV.UK, no date a).
- HIV support: Terrence Higgins Trust supports people living with HIV.
Your rights
Under the Equality Act 2010, HIV counts as a disability from diagnosis. Psoriatic arthritis can also count if it has a substantial, long-term effect on everyday life. This protects you from unfair treatment at work and in services (Equality Act 2010, s. 6 and sch. 1).
Quick questions
Can psoriasis turn into arthritis?
Psoriasis does not "turn into" arthritis, but about 1 in 4 people with psoriasis also develop psoriatic arthritis.
Does HIV cause psoriatic arthritis?
Research has not shown that it does, but people living with HIV are diagnosed with psoriasis and psoriatic arthritis more often (Damba et al., 2021).
The bottom line
Stiff joints, swollen fingers or toes, or nail changes? Speak to your GP early, and ask for your yearly joint check.
References
Arthritis UK (no date a) Psoriatic arthritis: symptoms, causes and treatment. Available at: https://www.arthritis-uk.org/information-and-support/understanding-arthritis/conditions/psoriatic-arthritis/ (Accessed: 4 October 2026).
Arthritis UK (no date b) Psoriatic arthritis [booklet]. Available at: https://www.arthritis-uk.org/media/4owb0b0w/a5-psoriatic-arthritis-booklet_digital.pdf (Accessed: 4 October 2026).
Arthritis UK (no date c) Exercising with arthritis. Available at: https://www.arthritis-uk.org/information-and-support/living-with-arthritis/health-and-wellbeing/exercising-with-arthritis/ (Accessed: 4 October 2026).
Ceccarelli, M. et al. (2019) 'HIV-associated psoriasis: epidemiology, pathogenesis, and management', Dermatologic Therapy, 32(2), e12806. Available at: https://doi.org/10.1111/dth.12806.
Chaiyabutr, C. et al. (2022) 'Retrospective study of psoriasis in people living with HIV: Thailand's experience', The Journal of Dermatology, 49(6), pp. 607–614. Available at: https://doi.org/10.1111/1346-8138.16352.
Damba, J.J. et al. (2021) 'Incidence of autoimmune diseases in people living with HIV compared to a matched population: a cohort study', Clinical Rheumatology, 40(6), pp. 2439–2445. Available at: https://doi.org/10.1007/s10067-020-05500-x.
Equality Act 2010, section 6. Available at: https://www.legislation.gov.uk/ukpga/2010/15/section/6 (Accessed: 4 October 2026).
Equality Act 2010, Schedule 1, paragraph 6. Available at: https://www.legislation.gov.uk/ukpga/2010/15/schedule/1/paragraph/6 (Accessed: 4 October 2026).
GOV.UK (no date a) Access to Work: get support if you have a disability or health condition. Available at: https://www.gov.uk/access-to-work (Accessed: 4 October 2026).
GOV.UK (no date b) Personal Independence Payment (PIP). Available at: https://www.gov.uk/pip (Accessed: 4 October 2026).
Haberman, R.H. et al. (2025) 'Racial and ethnic determinants of psoriatic arthritis phenotypes and disease activity', Rheumatology, 64(2), pp. 574–580. Available at: https://doi.org/10.1093/rheumatology/keae066.
NHS (2023) Psoriatic arthritis. Available at: https://www.nhs.uk/conditions/psoriatic-arthritis/ (Accessed: 4 October 2026).
NHS (2026) Psoriasis. Available at: https://www.nhs.uk/conditions/psoriasis/ (Accessed: 4 October 2026).
NICE (2012) Psoriasis: assessment and management (Clinical guideline CG153). London: National Institute for Health and Care Excellence. Available at: https://www.ncbi.nlm.nih.gov/books/NBK553610/ (Accessed: 4 October 2026).
Patel, A.A. et al. (2023) 'Racial and ethnic disparities in treatment initiation among patients with newly diagnosed psoriatic arthritis: a retrospective Medicaid claims database study', Rheumatology and Therapy, 10(5), pp. 1241–1253. Available at: https://doi.org/10.1007/s40744-023-00580-y.
Psoriasis UK (no date) About psoriatic arthritis. Available at: https://psoriasisuk.org.uk/information-and-support/page.aspx?ID=13 (Accessed: 4 October 2026).
Rouzaud, M. et al. (2014) 'Is there a psoriasis skin phenotype associated with psoriatic arthritis? Systematic literature review', Journal of the European Academy of Dermatology and Venereology, 28(Suppl 5), pp. 17–26. Available at: https://doi.org/10.1111/jdv.12562.
Tikly, M., Njobvu, P. and McGill, P. (2014) 'Spondyloarthritis in sub-Saharan Africa', Current Rheumatology Reports, 16(6), 421. Available at: https://doi.org/10.1007/s11926-014-0421-z.
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Important medical disclaimer
The content provided in this blog post is for educational and informational purposes only and does not constitute professional medical advice, diagnosis, or treatment. Always seek the advice of your GP, psychiatrist or another qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website. Never start, stop or change a prescribed medicine without speaking to your prescriber first.
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