Everything You Need to Known About Psoriasis

What is psoriasis?

Psoriasis is a chronic, systemic, inflammatory skin disorder in which there is an increase in the rate at which skin cells are produced and shed from the skin.

Normally, skin cells reproduce and mature as they move from the deeper layers of the epidermis (the outermost layer of the skin) to the surface. This process is called proliferation and usually takes approximately 28 days. In psoriasis, this process is accelerated, only taking about 4 days. The new skin cells reproduce too quickly and move toward the skin surface in an immature form, causing a build-up of silvery scale (dead skin cells). There is also an increased blood flow to the skin and a thickening of the epidermis, leading to the development of red, raised plaques (a plaque is a raised, red, scaling, well defined area more than 1cm in size).

Psoriasis can affect any part of the skin surface, but most commonly involves the elbows, knees, scalp, and the sacrum (lower back).

Psoriasis is a condition which tends to run in families. Several different genes have been identified but the exact way in which the disorder moves from generation to generation has not yet been established. What is known is that both the immune system and genetics are important in its development. So although the potential to develop psoriasis is genetically inherited, it is by no means certain that it will ever occur.

Environmental factors can also play a role in developing the condition. In some cases, emotional stress (like moving house, a divorce or bereavement), infection (such as a strep throat), injury to the skin or certain medications can trigger the first episode of psoriasis, while certain lifestyle factors (such as heavy drinking and smoking) may worsen it. Psoriasis is not contagious, infectious or the result of poor hygiene.

Psoriasis: the facts

Psoriasis may seem only skin deep, but it begins inside the body within the immune system. The red, scaly, flaky, and itchy patches occur when the skin cells grow too quickly as a result of inflammation caused by the body's immune system. Triggers for this abnormal immune reaction can include physical injuries or infections (in particular, a streptococcal throat infection), certain medicines, and emotional stress. Psoriasis varies in severity from person to person and can vary in severity in the same person at different times. Occasionally psoriasis can disappear without treatment but more usually, it is a chronic disease that requires treatment. Patches (also called plaques or lesions) can occur on various parts of the body, including the scalp, elbows, and or knees.

Co-morbidities (associated conditions)

People who have psoriasis are at risk of developing psoriatic arthritis, which commonly affects the joints of the fingers, toes and spine. Psoriasis is associated with a slightly higher risk of diabetes, high blood pressure, high cholesterol, cardiovascular disease (angina, heart attack, stroke), and obesity. There is also a strong association between psoriasis and depression.

Here are some of the symptoms associated with psoriasis and psoriatic arthritis. You may not experience all of these, but if you experience any of them, you should consult your doctor.

  • Red, scaly patches (also called plaques or lesions) with sharply defined edges, that occur most commonly on both elbows, both knees, the scalp, under arms, under breasts, natal cleft (groove between the buttocks) and genitalia, or at the site of an injury
  • If the scales are gently scraped off, a number of small, bleeding points can be seen underneath
  • Nail changes loosened, thickened or pitted nails (pits are small dents/ice pick like depressions on the surface of the nails)

Some symptoms associated with psoriatic arthritis

  • Joint pain, especially with redness, swelling, and tenderness
  • Pain in your heel(s) or tennis elbow
  • A finger or toe that was completely swollen (sausage shaped) and painful for no apparent reason
  • Morning stiffness/pain in the back that improves with movement
How is it diagnosed?

Most cases of psoriasis are diagnosed by GPs, who is usually best placed to give advice on how to manage and treat your condition; sometime however onward referral to a dermatologist may be necessary.

What can be done?

Psoriasis varies in severity from person to person, and in the same person at different times. Occasionally psoriasis can disappear spontaneously, but more usually, it is a chronic condition that requires treatment. If you discover that certain things make your psoriasis worse, try to avoid them. It should be noted that all degrees of psoriasis can be treated effectively. The treatment is not a cure, but it will ensure a better quality of life.

The future

Psoriasis affects millions of people around the world. It is important to remember that psoriasis does not define you as a person. There are many different treatment options. Finding the treatment that works best for you can help you feel better about your condition.

Potential triggers


In those with a family history of psoriasis, a streptococcal throat infection sometimes triggers the first symptoms of psoriasis. Guttate psoriasis often develops in this way. Typically, patients will report a history of a sore throat approximately 2 weeks before the widespread appearance of small, red teardrop shaped patches.

Emotional stress

In those with a genetic predisposition to develop psoriasis, emotionally stressful events, such as an important exam or the death of a loved one, can trigger the first episode of psoriasis or worsen an existing flare-up.


Certain medications, such as lithium, beta blockers, and anti-malarials, have been reported to aggravate psoriasis symptoms. To prevent this from happening, ensure that your doctors knows that you have psoriasis (even if you haven't had any symptoms in years). Stopping some medicines abruptly can also lead to flare-ups, so be sure to talk to your doctor about the best way to taper off a medication and when it's appropriate to do so.

Skin Injury (Koebner phenomenon)

In about one third of patients, physical trauma to the skin, such as a cut, scrape, insect bite, or burn, can cause psoriasis to develop at the site of the injury. This occurrence was first described by a doctor named Koebner in 1872, and was subsequently called the Koebner phenomenon.


Sudden exposure to cold weather can sometimes trigger a flare-up. In general, psoriasis tends to improve in warmer climates and worsen in colder ones.

Lifestyle factors

Stress, alcohol, cigarette smoking, and obesity have all been associated with flare-ups, so it can be useful to look at changing lifestyle behaviours, and seek out healthy ways to manage stress levels. Your psoriasis may improve by limiting your alcohol intake, giving up smoking and maintaining a healthy weight. Exercise is good to relieve stress and to reduce weight.

Types of psoriasis

Scalp psoriasis

The scalp is one of the most common sites to be affected by psoriasis, and sometimes it is the only area of involvement. It usually extends to, or just beyond the hairline and commonly occurs behind the ears. Scalp psoriasis may appear in the form of red, raised plaques covered in fine white flakes (similar to dandruff), or the scale may become thickened, with an appearance like cradle cap.

Nail Psoriasis

Nail psoriasis can affect the nails of both the hands and feet. Many changes can occur, for example: thickening, loosening, changes in colour and the appearance of pits (pits are small dents/ice pick like depressions on the surface of the nails).


Localized pustular psoriasis is a form of psoriasis that is confined to the palms of the hands and/or the soles of the feet. The palms and soles become red and scaly, with white/yellow sterile pustules (blisters of non-infectious pus). The pus consists of white blood cells. It is not an infection and is not contagious. Reddish-brown patches are present as the pustules resolve. Psoriasis affecting the palms and soles can severely limit everyday activities, for example, walking can become difficult. This can be a very painful and debilitating form of psoriasis.

Generalized pustular psoriasis is extremely rare. It can occur on any part of the body and is characterized by the development of white/yellow sterile pustules, on a background of red skin. It is not an infection and is not contagious. It tends to be preceded by other forms of psoriasis and is often trigged by an infection, or the withdrawal of certain medications.


Guttate psoriasis is the second most common form of psoriasis. The word guttate' comes from the Latin for drop (guta) and this type of psoriasis occurs more commonly in children and young adults. It usually has a sudden onset, with the widespread appearance of small red teardrop shaped patches less than 1.5cm in size. The onset is often preceded by a streptococcal throat infection. In many cases, the condition disappears by itself after a few weeks or months.

Plaque Psoriasis (psoriasis vulgaris)

Plaque psoriasis is the most common form of psoriasis, affecting approximately 90% of patients. It is a chronic, inflammatory skin disorder in which there is an increase in the rate at which skin cells are produced and shed from the skin, appearing in the form of raised, red patches covered with a silvery scale (dead skin cells). The plaques can vary in number, size, and location but are often circular or oval shaped, and most frequently occur on the knees, elbows, scalp and sacrum (lower back). The plaques are often itchy and painful, and can crack and bleed.

The extent of the skin surface involved can range from 1 to 100%. Erythrodermic psoriasis is the term used to describe instances where almost the entire body surface is involved, and is characterised by red skin with a diffuse, fine, peeling scale. It is quite rare, generally occurring in those who have unstable plaque psoriasis.

Psoriatic Arthritis

What is psoriatic arthritis?

Arthritis means inflammation of one or more joints. Psoriatic arthritis (PsA) is a chronic, inflammatory form of arthritis associated with psoriasis, that can cause pain, swelling and damage to joints, but can be treated. PsA is less common than other forms of arthritis such as osteoarthritis or rheumatoid arthritis.

What causes PsA?

PsA is an autoimmune disease, occuring when the immune system attacks the joints and also tendons. While the exact cause is not known, research points to the involvement of several different genes. Progression of disease may be genetically determined but environmental factors may also play an important part in triggering PsA.

How common is PsA?

The prevalence of PsA is estimated to be between 0.3 1% of the general population. However, studies have indicated that up to 42% of psoriasis patients can have accompanying PsA. The incidence of PsA is slightly higher in women, with peak onset occurring between 35-45 years of age. Onset may be gradual with mild symptoms developing slowly over a period of years, or progress more rapidly to become severe and destructive.

Appearance of symptoms

For the majority of patients, psoriasis develops first, commonly around 10 years before PsA. Joint problems start before psoriasis in approximately 16% of patients, while 15% develop skin and joint problems simultaneously. Severe skin disease or psoriasis affecting the nails may indicate a risk for developing PsA.

Some symptoms associated psoriatic arthritis

Symptoms can vary greatly from patient to patient. Let your doctor know if you have the following symptoms which may indicate psoriatic arthritis:

  • Joint pain especially with redness, swelling and tenderness.
  • Dactylitis inflammation of an entire digit, either a finger or toe which swells up to a sausage shape and can be painful.
  • Nail changes loosened, thickened or pitted nails (pits are small dents/ice pick like depressions on the surface of the nails).

It has been suggested that the presence of 20 nail pits distinguishes patients with PsA from those with rheumatoid arthritis and psoriasis.

  • Morning stiffness/pain in the back that improves with movement.
  • Pain in your heel(s) or tennis elbow.
Diagnosis and referral

A screening tool for PsA called the Psoriasis Epidemiology Screening Tool' (PEST) is available to help general practitioners and dermatologists identify patients for further evaluation by a rheumatologist. It is recommended that patients with psoriasis who do not have a diagnosis of PsA complete a PEST questionnaire annually and are referred on to a rheumatologist where necessary i.e. those patients scoring 3 or more out of 5 (please see diagram).


If a diagnosis of PsA is confirmed by your doctor, treatment is aimed at reducing pain, inflammation, and preventing longer term damage to joints. As the inflammatory process is similar in the skin and joints, treatment targeting one aspect of the condition may benefit the other as well.


Treatment recommendations may include:

  • Non-steroidal anti-inflammatory drugs (NSAIDs)

This class of medication helps to reduce inflammation, joint pain and stiffness. However, they do not improve the long term outcome of the disease.

  • Steroid injections

Steroid injections into the joint may be recommended where joints are particularly painful and inflamed.

  • Disease modifying anti-rheumatic drugs (DMARDs)

This class of medication differs from the others mentioned above because they can help stop the progression of joint damage, and are often prescribed in combination with NSAIDs and/or steroid injections. DMARDs, which are drug that affects the immune system, are used to treat moderate-to-severe psoriasis and PsA. Regular blood tests are taken to monitor for side-effects.

  • Biologic agents (injectable medication)

If you are taking a DMARD and not getting symptom relief, or if you are experiencing side effects, your doctor may prescribe a biologic agent.

Biologic agents (medicines based on compounds made by living cells) offer another option for the treatment of psoriasis and PsA. These drugs target specific parts of the immune system that are responsible for causing inflammation in psoriasis and PsA. These drugs help restore balance to the immune system.

Biologics are given by injection under the skin or intravenously (IV), and they target and effectively improve psoriasis and PsA symptoms. The treatment schedule varies from drug to drug. There is always some risk associated with taking any medication. Talk to your doctor about the risks and benefits of any medication you take. Non-medication therapies can also be very helpful in the treatment of PsA. For example:

  • Physiotherapy to help maintain muscle strength, range of movement, and function of affected joints.
  • Occupational therapy advice on ways to reduce strain and prevent further damage to affected joints when going about everyday activities, both at home or at work (including equipment and adaptations).
  • Podiatry for assessment of foot care needs, provides advice on footwear and can fit moulded insoles to help keep the foot in the best alignment (position).
  • Dietitian advises on healthy diet and can help with food choices when weight loss is important. Being overweight puts extra strain on joints, especially those of the back and legs.

A number of healthcare professionals may therefore be involved in your care. It is likely though that your dermatologist and rheumatologist will continue to jointly manage your care along with the rest of your team. Additional support and guidance is available from Arthritis Ireland.

Living with psoriasis

Identifying what triggers or aggravates your symptoms can help you find a more effective treatment plan. For example, in about one third of people with psoriasis, physical trauma to the skin, such as a cut, scrape, insect bite, or burn, can cause psoriasis to develop at the site of the injury. This occurrence was first described by a doctor named Koebner in 1872, and was subsequently called the Koebner phenomenon.

General Skin Care Tips

You may wish to consider the following psoriasis skin care tips below:

  • Be gentle don't scrub your skin or take a bath or shower in hot water use warm water only. Pat your skin dry after cleansing rather than rubbing and irritating it.
  • Keep your skin well moisturized dry skin itches, and you may be tempted to scratch. If you apply a moisturizer immediately after your shower or bath, it will help lock in moisture. Emollients and soap substitutes form an important part of treatment.
  • Keep nails trimmed you're less likely to scratch yourself.
  • If facial psoriasis is a problem, consider skipping a day between shaves. Be sure to change your razor blade frequently or opt for an electric razor.
  • Wear cotton next to your skin cotton is much less likely to irritate your skin compared with other fabrics, such as wool. If your skin is irritated, you're more likely to scratch.
  • Sun protection while psoriasis can benefit from sunlight, sunburn can cause psoriasis flares.
Lifestyle Factors

Certain lifestyle factors, such as stress, alcohol, cigarette smoking, and obesity have all been associated with flare-ups, so it can be useful to look at changing lifestyle behaviours, and seek out healthy ways to manage stress levels.

  • Consider keeping a diary to pinpoint situations, places or events that trigger your stress understanding your triggers can empower you and help make stress more manageable.
  • Be sure to exercise regularly, but also to get adequate rest. Exercise and rest help maintain your health and reduce stress. They also reduce the risk of heart disease (which is higher in those with psoriasis).
  • Avoid excessive alcohol. As well as making psoriasis worse, it can contribute to low mood, anxiety, obesity and heart disease. Do not smoke. Smoking makes psoriasis worse and increases your risk of heart disease.
  • Eat a healthy diet. Obesity makes psoriasis worse and increases the risk of heart disease, high blood pressure and cholesterol. Recommended waist measurements are less than 32 inches (80cm) for women and less than 37 inches (94cm) for men. A lifelong healthy diet is important for everyone.

How is psoriasis treated?

The treatment of psoriasis depends on its severity and location, and can be divided into four main categories: topical treatments (creams or ointments applied directly to the skin), ultraviolet light therapy (also called phototherapy, delivered in hospital dermatology departments), systemic medications (medicines that work inside your body) or biologic treatments (medicines based on compounds made by living cells). The use of emollients and soap substitutes also form an integral part of treatment. Talk with your doctor to find a treatment regimen that is most appropriate for you.

For psoriasis, the good news is that there is a range of treatment options available, as well as on-going research examining potential new treatments. Be sure to talk to your doctor about your symptoms and progress. Only your doctor, working together with you, can choose the right treatment for your condition.

For more detailed information please consult our booklet, What you need to know about Psoriasis.

Emotions and behaviours

Psoriasis can impact your life in many ways, including your emotions and behaviour.

Psoriasis can influence your emotions and behaviours.

Psoriasis can impact your life in many ways and may sometimes make you feel embarrassed about your body. Because flare-ups are often visible to others, you may feel self conscious or anxious. The stress caused by psoriasis may actually trigger further flare-ups or worsen existing psoriasis.

Because there is still no cure for psoriasis, treatment focuses on reducing and controlling symptoms this can be frustrating, can wear you our emotionally and some people diagnosed with psoriasis may feel depressed. Skin lesions may make you feel unattractive, some people feel embarrassed about their bodies, or even stay at home to avoid social situations. Some have difficulty interacting with co-workers, and even family and friends, because they feel self-conscious about the appearance of their skin.