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Dr. Björn Thomas
5 mins read

Is Psoriasis Genetic?

Person scratching their arm, which has psoriasis.

Written By Dr Bjorn Thomas | Last Updated August 2026

If you have psoriasis, you may have looked around your family and wondered where it came from. Perhaps a parent has it. Maybe an aunt or grandparent remembers having a similar rash. Or perhaps, despite searching through your family history, you cannot identify anyone else with psoriasis at all.

Yes. Genetics plays an important role in psoriasis, but psoriasis is not inherited in a simple or predictable way. Having a parent with psoriasis increases your risk, but it does not mean you will definitely develop the condition. Equally, psoriasis can occur without any known family history.

In clinic, I explain psoriasis as the result of several factors coming together. Genetics can create susceptibility, the immune system plays a central role, and environmental or personal triggers may influence whether psoriasis appears and when it flares.

In this guide, I will look more closely at how psoriasis runs in families, what researchers know about the genes involved, what your family history really means for your personal risk, and whether you can pass psoriasis on to your children.

Key Takeaways

  • Psoriasis has an important genetic component, but it is not caused by one single psoriasis gene.
  • Family history increases risk, but does not determine whether someone will develop psoriasis.
  • People without a family history can still develop psoriasis.
  • Psoriasis usually develops through a combination of genetic susceptibility, immune activity and other triggers.
  • Stress, infections, certain medicines, smoking, alcohol, obesity and skin injury can trigger or worsen psoriasis in some people.
  • Genetic testing is not routinely needed to diagnose or treat most cases of psoriasis.

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Is Psoriasis Genetic? The Direct Answer

Yes, psoriasis is partly genetic and having an affected family member increases your likelihood of developing it. 

However, it is a complex, polygenic condition rather than one caused by a single inherited gene. Multiple genetic changes influence risk. These changes can interact with your immune system and other factors. This is why one member of a family may have psoriasis while a sibling never develops it, and why psoriasis can also occur in someone whose parents are unaffected.

Why Having A Psoriasis Gene Does Not Guarantee Psoriasis

One of the most important points to understand is that genetic susceptibility is not the same as a diagnosis.

You may inherit genetic variations that increase your chances of psoriasis without ever developing the condition. Equally, psoriasis may first appear after a trigger such as illness, stress, injury to the skin, or exposure to certain medicines.

The Psoriasis and Psoriatic Arthritis Alliance, or PAPAA, explains that psoriasis is multigenic and notes an interesting finding from twin studies. Even identical twins, who share the same genetic material, do not always both develop psoriasis. This is strong evidence that genes alone do not provide the full answer.

You can read more in PAPAA’s guide to the genetics of psoriasis and psoriatic arthritis.

Of course, there is rarely one identifiable event. For many patients, psoriasis appears without any obvious explanation.

What Does Family History Mean For Your Psoriasis Risk?

A family history does matter. However, it is important to talk about risk carefully because different studies and patient organisations report different figures.

Overall, landmark studies estimate that approximately 70% of ‘the risk’ is inherited. This risk is lower, at approximately 15%, if only one parent has the condition.

I would not treat those percentages as a precise personal prediction. Genetics/heritabulity is complicated, and population estimates cannot tell us exactly what will happen to one individual child.

The more useful message is this:

Your family history is clinically useful, but it is not a set indication of whether you will be affected. It helps to look at it like this:

  • One affected parent increases the risk.
  • Two affected parents increase the risk further.
  • Many children of people with psoriasis never develop it.
  • Some people develop psoriasis with no obvious affected relatives.

Can You Pass Psoriasis On To Your Children?

Psoriasis itself is not passed from parent to child in a simple, predictable way. What may be inherited is a combination of genetic variations that increases your risk. 

A child may inherit some of that susceptibility and never develop psoriasis. Another child, in the same family, may develop it. 

Having psoriasis is not, in itself, generally a reason to avoid having children. If you are planning a pregnancy and take systemic treatment for psoriasis, discuss this with your dermatologist or prescribing clinician in advance. Some treatments may need to be stopped or changed before conception or during pregnancy.

Which Genes Are Linked To Psoriasis?

Researchers have identified many different parts of our DNA that are associated with psoriasis. One of the best-known is a susceptibility region called PSORS1, located on chromosome 6.

PAPAA explains that PSORS1 has a particularly strong association with psoriasis that begins earlier in life and with cases where there is a family history.

However, there is no single psoriasis gene that explains every case.

Instead, researchers have identified multiple genetic regions connected with:

  • How the immune system recognises cells and proteins.
  • How inflammation is switched on and controlled.
  • The activity of immune pathways involved in psoriasis.
  • How skin cells respond to inflammatory signals.

This research is important not just because it tells us more about inherited risk. It has also helped improve our understanding of the immune pathways involved in psoriasis, which in turn has contributed to the development of highly targeted treatments.

For most patients, though, I do not need a genetic test to diagnose psoriasis. Diagnosis is generally based on the appearance and distribution of the skin changes, medical history and examination. Occasionally, if the diagnosis is unclear, a skin biopsy may be helpful.

What Can Trigger Psoriasis If You Are Genetically Prone?

Having a genetic tendency towards psoriasis does not mean symptoms will automatically appear.

A range of factors may trigger the first episode or cause existing psoriasis to flare. The NHS lists recognised triggers, including:

  • Stress
  • Alcohol
  • Smoking
  • Obesity
  • Pregnancy
  • Certain medicines
  • Infections, including streptococcal infection
  • Cuts, scratches or grazes to the skin
  • Sunlight in some people

Not everyone has the same triggers. In fact, some patients never identify a clear trigger at all.

Stress

Stress is one of the triggers patients mention to me most often. The relationship can also become cyclical. Psoriasis causes distress, then stress contributes to a flare, which causes further distress.

Infections

Some forms of psoriasis have a particularly clear connection with infection. Guttate psoriasis, for example, can appear after a streptococcal throat infection, especially in children and younger adults.

Skin Injury

Psoriasis can sometimes develop where the skin has been scratched, cut, burned or otherwise injured. This is known as the Koebner phenomenon.

Medicines

Certain medicines can trigger or worsen psoriasis in susceptible people. I always take a full medication history when assessing a new or unexpected flare.

Understanding triggers can be useful, but I am careful not to make patients feel responsible for their psoriasis. You did not cause your condition by being stressed, eating the wrong food, or failing to follow the perfect skincare routine.

Can You Develop Psoriasis With No Family History?

Yes, this can happen. I regularly see patients with clear psoriasis who cannot identify a single affected relative, and a missing family history does not rule out the diagnosis.

Often this is because previous generations had mild, undiagnosed psoriasis, for example scalp symptoms mistaken for dandruff, or minor elbow plaques that were never investigated. Genetic susceptibility can also be present in a family without ever causing visible disease.

This is why I treat family history as one piece of clinical information, not a diagnostic requirement.

Do Genetics Affect When Psoriasis Starts?

PAPAA notes that psoriasis beginning before or around the age of 40 is more often associated with family history and the PSORS1 susceptibility region. Later-onset psoriasis is less commonly associated with a strong family history.

However, these are broad patterns, not rules.

The NHS states that psoriasis can begin at any age, although symptoms often first appear between 15 and 25 or between 50 and 60.

I see psoriasis as a condition with considerable individual variation. One person may develop mild scalp psoriasis in their teens. Another may experience their first major flare in middle age. A third may have intermittent plaques for decades.

Genetics may influence susceptibility and age of onset, but it cannot tell us exactly how severe one person’s psoriasis will be or how their condition will behave throughout life.

Does Psoriasis Genetics Affect Treatment?

Usually, I do not choose an everyday psoriasis treatment based on a genetic test.

Instead, I look at:

  • The type of psoriasis.
  • How much skin is affected?
  • Which areas of the body are involved?
  • How severe the itching, pain or scaling is.
  • Whether nails or joints are affected.
  • The effect on sleep, work, confidence and quality of life.
  • Previous treatment responses.
  • Other health conditions and medicines.

Treatment may include emollients, topical steroid preparations, vitamin D-based treatments, phototherapy, oral medicines or injectable biologic treatments, depending on severity and individual circumstances.

Genetics research has, however, made a major contribution to modern psoriasis treatment. By identifying immune pathways involved in psoriasis, researchers have helped develop medicines that target particular inflammatory signals much more precisely.

So, although I may not need to send off samples to test your genes in a lab, genetics research has still shaped many of the treatments that are available to individuals with this condition.

What About Psoriatic Arthritis And Family History?

Psoriasis is not only relevant to the skin.

Some people with psoriasis develop psoriatic arthritis, an inflammatory condition that can cause joint pain, swelling and stiffness. The NHS advises medical review if you have psoriasis alongside recurring joint pain, stiffness or swelling.

I always encourage patients to mention joint symptoms, even if they initially booked for a skin problem.

Symptoms worth discussing include:

  • Persistent joint pain or swelling.
  • Morning stiffness that takes time to ease.
  • Swollen fingers or toes.
  • Heel pain.
  • Changes to the nails alongside joint symptoms.

Having psoriasis does not mean you will develop psoriatic arthritis, but recognising symptoms early matters.

When I Recommend Seeing Me for Assessment

You do not need to wait until psoriasis becomes severe to ask for help.

I would suggest an assessment if:

  • You have a new persistent scaly rash and are unsure what it is.
  • Psoriasis is spreading or becoming harder to manage.
  • Your treatment is no longer working.
  • Your scalp, nails, hands, feet, face or genital area are significantly affected.
  • Symptoms are disrupting sleep, work or confidence.
  • You develop recurring joint pain, stiffness or swelling.
  • You are planning a pregnancy while taking psoriasis medication.

A Note On Who Will Treat You

I am Dr Björn Thomas (MBBS, PhD, MRCP), Consultant Dermatologist and founder of the Thomas Clinic. When I assess psoriasis, my aim is not simply to look at the visible patches. I consider the pattern of disease, possible triggers, previous treatment, family history, nail changes, joint symptoms and how the condition affects daily life.

Book A Psoriasis Consultation

If you’ve been asking ‘is psoriasis genetic?’ I can help you understand what your individual situation means.

A consultation can confirm whether you have psoriasis, assess its severity and give you a clear, personalised psoriasis treatment plan.

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About The Author

Dr. Thomas is a Consultant Dermatologist with specialities in general dermatology, skin cancer, and advanced dermatologic therapies. He also previously held a substantive consultant role at Guy’s and St Thomas’ NHS Foundation Trust and is part of the Skin Tumour Unit at St John’s Institute of Dermatology.

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