Psoriasis Causes

What Causes Psoriasis?

The question of what triggers psoriasis is an interesting one. The exact cause of the disease is not fully understood. Rather, it appears that a number of combined factors contribute towards psoriasis.

Psoriasis has been with us for thousands of years. When Egyptian mummies were unearthed, archeologists identified psoriasis amongst their ailments. The ancient Greeks also had a word for it; psora, meaning "to itch". But although psoriasis was prevalent in ancient times, physicians struggled to identify it's cause.

Brief History of Psoriasis

Even the most respected medical minds were baffled by psoriasis. Greek father of medicine, Hippocrates (460-377 B.C.) began a very early form of coal tar treatment on his patients - he also prescribed topical arsenic. Noted physician Galen (133-200 A.D.) identified psoriasis as a skin disease through clinical observation and was the first to call it psoriasis. Along with arsenic, he suggested applying broth in which a viper had been boiled. Despite physicians developing these early treatments, the cause still remained somewhat of a mystery. Due to its appearance, psoriasis was often lumped in with similar skin disorders that were believed to be contagious, psoriasis was often confused with leprosy.

Psoriasis - immune system cause

Fast forward a century or two and the 1960's saw the first studies into psoriasis being immune system related. It was eventually confirmed that it is indeed an autoimmune disease - in psoriasis the immune system attacks itself.

Psoriasis - a genetic cause

Besides the immune connection, genetics were also being considered. The early nineties saw the Human Genome Project, a search to identify the genes that determine psoriasis. In 2012 scientists led by Washington University School of Medicine identified the first gene directly linked to the most common form of psoriasis. Research revealed that rare mutations in the CARD14 gene - when activated by an environmental trigger - could lead to plaque psoriasis. 

If you have psoriasis, it is possible that someone in your family may have had it too. One in three people with psoriasis reports having a relative with the disease. And researchers say that up to 10% of the general population may inherit one or more genes that predispose them to psoriasis.

A genetic predisposition to a particular illness does not mean you're guaranteed to get it, in fact only 2% to 3% of people with the gene actually go on to develop the disease.. It means that there is a higher than average chance, but the predisposition still requires a trigger to kick start the condition. 

Environmental triggers for psoriasis can include;

  • an infection, such as strep throat
  • injury to the skin
  • a cut or bug bite
  • certain medications
  • a poor diet
  • smoking
  • excessive alcohol consumption
  • stress
  • Vitamin D deficiency
  • Certain medications — including lithium, which is prescribed for bipolar disorder, high blood pressure medications such as beta blockers, antimalarial drugs, and iodides

Can I Catch Psoriasis?

No, absolutely not. Psoriasis is not contagious in anyway. You can't catch psoriasis, neither can you pass it on to others through bodily contact. 

Can a Poor Diet Cause Psoriasis? 

On a purely logical level it makes complete sense that diet would play a role in skin disease, after all it's widely acknowledged these days that diet is vital when it comes to the prevention of much more life threatening illnesses such as heart disease and cancer. If diet affects the body's organs in these serious diseases, surely it can impact the largest organ in our body (the skin). 

Medical professionals accept that diet can be responsible for increasing and decreasing inflammation, and it's agreed that there is a connection between psoriasis and inflammation in the body, so eating an anti-inflammatory diet for psoriasis can only be a positive. 

Furthermore, researchers found several studies linking obesity to an increased risk for psoriatic disease. These studies indicate that a higher body mass index (BMI) is associated with an elevated risk for developing psoriasis and psoriatic arthritis, as well as increased disease severity. Fat cells secrete cytokines, which are proteins that can trigger inflammation, so if you lose weight, it stands to reason you may be reducing fuel for the inflammatory fire.

"We all have to eat during the day," said Dr. Wilson Liao, who recently co-authored a three-part series analysing the effect of diet on psoriasis. "If there's a way to turn that requirement into a benefit for our health and for psoriasis, then why not?"

The series, published in the Journal of the American Academy of Dermatology, explores available research on:

  • weight loss
  • gluten-free diets
  • nutritional supplements

More studies are needed, Liao said. "We also need more randomised, clinical trials to prove that these dietary modifications work."

Liao's research team plans to conduct a survey of psoriasis patients to learn more about their interest in different diets. His research team are interested in further exploring the importance of diet in managing psoriatic disease.

In 2013, a small clinical trial based in Denmark reported what they believed to be the first results of a study on the effects of weight loss using the severity of psoriasis as a primary endpoint. The researchers found that obese patients with psoriasis who lost weight through a low-calorie diet experienced a significant improvement in their quality of life compared with obese psoriasis patients who didn’t lose weight.

In the randomised clinical trial, 27 patients were assigned to an intervention group that followed a low-calorie diet, and 26 patients were assigned to a control group that continued to eat ordinary healthy foods. The participants met every 2 weeks for a total of eight group sessions led by the study dietitian. The patients on a low-calorie diet ended up losing nearly 34lbs over 4 months, and reported improvements in both their psoriasis symptoms and their overall quality of life 6.

It's widely accepted that fruits and vegetables are an important part of any healthy diet, but these may be especially important for patients with psoriasis. A 1996 study 7, found an inverse relationship between an intake of vegetables, fresh fruit and psoriasis. All of these foods are high in healthy antioxidants.

Another study published a year later found that patients with psoriasis had lower blood levels of glutathione. Glutathione is a powerful antioxidant found in garlic, onions, broccoli, kale, collards, cabbage, and cauliflower. Scientists speculated that a diet rich in antioxidants may help.

Find out more about my plant based diet protocol for psoriasis here

Can alcohol cause psoriasis?

Heavy drinking has been linked to both an increase in the risk and the severity of psoriasis. On a very logical and simplistic level, alcohol can have the following negative impacts on psoriasis;

  • Alcohol lowers your immune function, which can increase your risk of skin infection
  • Drinking alcohol can increase inflammation which triggers psoriasis flare-ups
  • Alcohol is responsible for dehydration in the body and drying out the skin

A study carried out by researchers from Brigham and Women’s Hospital, Harvard Medical School and Boston University and funded by the National Institutes of Health and the National Cancer Institute 4. The study was published in the peer-reviewed medical journal, Archives of Dermatology, it examined the drinking habits of more than 80,000 US nurses over an average of 14 years, during which 1.4% developed psoriasis. Women who drank an average of 2.3 or more alcoholic drinks a week were 72% more likely to develop the condition.

For men, excess alcohol intake has been found to be a risk factor for the development and increased severity of psoriasis1, 2. More than 80 grams of alcohol a day has also been associated with less treatment-induced improvement in men.3

In the UK, drinks are measured in units - one unit is equal to 8 grams. A pint of beer (568ml) or a large glass of wine (250ml) both contain around 2.5 units or 20 grams of alcohol, so four drinks would be equivalent to 80 grams.

Furthermore alcohol can have dangerous side effects when combined with certain psoriasis medications, such as methotrexate or acitretin / Soriatane in women of child-bearing potential.

Can smoking cause psoriasis? 

A study published in 1999 led by Luigi Naldi, M.D 5found a much higher risk of psoriasis in smokers. Dr. Naldi's group compared people with psoriasis to people with other skin conditions; as many as one in five cases of psoriasis were related to smoking.

According to Dr. Naldi, "We know that smoking affects the onset of psoriasis and its clinical appearance. Smoking about doubles a person's risk of getting psoriasis; the risk increases with the number of cigarettes smoked per day, and is higher in women than men. The risk for women who smoke more than 20 cigarettes per day is about 2.5 times greater than the rate of nonsmokers, and in men the risk is about 1.7 times greater than the rate of nonsmokers."

Dr. Naldi points to nicotine as a possible culprit in altering the immune system and possibly skin cell growth, as well as directly affecting skin inflammation

Can stress cause psoriasis?

It's widely acknowledged that psoriasis and stress are intricately linked. Although psoriasis is a genetic condition, environmental factors such as a stressful life event often trigger it, according to the American Academy of Dermatology. Having psoriasis is stressful in itself, which contributes to flare-ups, too. Often creating a vicious circle that's difficult to break. 

Because stress can have an impact on the immune system, doctors have long suspected a link between stress and psoriasis, and recent research supports this theory. "Psoriasis is very stress dependent. It flares very easily when patients are under stress, and it tends to improve when they're relaxed," says Vesna Petronic-Rosic, MD, dermatologist and associate professor of medicine at the University of Chicago Medicine. 

There can be a temptation to slip into a poor, sugar rich diet, excess alcohol consumption or smoking to alleviate stress. As noted above, these practices are extremely counterproductive for both stress and psoriasis. Healthy, natural stress management techniques that can help include;

  • Exercise - exercise in general can be hugely beneficial for reducing stress, gentle breathing exercises such as yoga especially can offer some fantastic benefits
  • Meditation - practicing meditation has been proven to reduce stress levels. Not sure where to get started? Download our free guided meditation here 
  • Relaxation - something as simple as taking time for yourself, enjoying a long soak in a bath filled with dead sea salts and lavender oil can offer wonderful relaxing benefits

A 2013 review notes that 68 percent of adults with psoriasis experience flare-ups after stressful incidents. Scientists are unsure as to precisely why stress makes psoriasis worse, but they believe it relates to the impact that stress has on inflammation. This 2014 study notes that stress factors can increase the immune system response involved in inflammation. This 2013 study also suggests that the increase in inflammatory cells that results from stress aggravates the symptoms of psoriasis.

Being under psychological stress can lead to physical inflammation in the body. In turn, increased inflammation may make psoriasis symptoms worse.

Additionally, one study found that women with depression were at a higher risk of developing psoriasis. While researchers are still exploring the relationship between depression and inflammation, their connection may be influential in future psoriasis treatments.


What do you believe your psoriasis causes and triggers are? Share your thoughts in the comments below.  


          1. Poikolainen, K., Reunala, T., Karvonen, J., Lauharanta, J. & Kärkkäinen, P. Alcohol intake: a risk factor for psoriasis in young and middle aged men? BMJ 300, 780–3 (1990).
          2. Gupta, M. A., Schork, N. J., Gupta, A. K. & Ellis, C. N. Alcohol intake and treatment responsiveness of psoriasis: a prospective study. J. Am. Acad. Dermatol. 28, 730–2 (1993).
          3. Gupta, M. A., Schork, N. J., Gupta, A. K. & Ellis, C. N. Alcohol intake and treatment responsiveness of psoriasis: a prospective study. J. Am. Acad. Dermatol. 28, 730–2 (1993).
          4. Qureshi AA, Dominguez PL, Choi HK et al. Alcohol Intake and Risk of Incident Psoriasis in US Women. Archives of Dermatology 2010. Published online August 16 2010
          5. Naldi  LParazzini  FBrevi  A  et al.  Family history, smoking habits, alcohol consumption and risk of psoriasis.  Br J Dermatol. 1992;127212- 217
          6. Brown AC, Shankar P. Psoriasis, diet, and dietary supplements—A review [abstract]. J Am Diet Assoc. 2011;111 (suppl 2):A33. 4. Jensen P, Zachari
          7. Dietary factors and the risk of psoriasis. Results of an Italian case–control study L. NALDI  F. PARAZZINI L. PELI  L. CHATENOUD T. CAINELLI First published: January 1996 
          8. Clin Chim Acta. 1999 Nov;289(1-2):23-31. Antioxidants and lipid peroxidation status in the blood of patients with psoriasisKökçam I(1), Naziroğlu M


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