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Psoriasis is a chronic, systemic inflammatory skin disorder that affects at least 73,000 people in Ireland.

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.

Among people living with psoriasis, this process is accelerated. 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).

At the same time, blood flow to the skin is increased and a thickening of the epidermis occurs, leading to the development of red, raised plaques (a plaque is a raised, red patch often covered with a silvery white build-up of scale).

Psoriasis Booklet

Our What you need to know about psoriasis booklet has been prepared by people with psoriasis, dermatology nurses and consultant dermatologists to help you understand your condition, talk with your doctor, learn about available treatments, and find useful tips for living with psoriasis.

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

What causes psoriasis?

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 those who are susceptible. In some cases, emotional stress (like moving house, a divorce or bereavement), infection (such as a streptococcal throat), injury to the skin (referred to as Koebner phenomenon) or certain medications (e.g. lithium, beta-blockers, antimalarials) can trigger the first episode of psoriasis, while certain lifestyle factors (such as drinking too much alcohol and smoking) may worsen it.

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.

Symptoms associated with psoriasis

  • 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)

Types of psoriasis

  1. Plaque psoriasis is the most common form of psoriasis, affecting approximately 90% of patients. The plaques can vary in number, size, and location but the sites most frequently affected, are the knees, elbows, scalp and sacrum (lower back). The plaques are often itchy and painful, and can crack and bleed
  2. Guttate psoriasis usually has a sudden onset with the widespread appearance of small, red teardrop shaped patches. The onset is often preceded by a streptococcal throat infection. In many cases, the condition disappears by itself after a few weeks or months. This type of psoriasis occurs more commonly in adolescents or young adults.
  3. Flexural psoriasis can occur in skin folds (flexures), such as under the breasts, in the armpits or the groin. The plaques are usually red, smooth and shiny. There is very little or no scale, due to the presence of sweat, which moistens the keratin (dead skin cells) and prevents scaling. Painful superficial skin cracks or tears (fissures) sometimes occur in skin creases.
  4. Genital psoriasis often falls under the heading of flexural psoriasis, and can affect the male and female genitalia.
  5. Scalp psoriasis is one of the most common sites to be affected by psoriasis, and sometimes it is the only area of involvement. Almost 80% of people with psoriasis will have scalp involvement at some point in their lives. Scalp psoriasis may appear in the form of fine white flakes (similar to dandruff) or as red, raised, scaly plaques which can extend to, or just beyond the hairline and commonly occurs behind the ears. Visit our resources page to read our Scalp Psoriasis leaflet.Psoriasis may also affect the face, particularly around the hairline.
  6. Nail psoriasis can affect the nails of both hands and feet. Changes may include: thickening, loosening, changes in colour and the appearance of pits (pits are small dents/ice pick like depressions on the surface of the nails). Nail changes are often associated with psoriatic arthritis.
  7. While the palms of hands and soles of feet may be involved in both plaque and guttate psoriasis (and on occasion, may only affect these areas), another form of psoriasis that is confined to these areas, is called palmo-plantar pustulosis. This form of psoriasis is confined to the palms of the hands/or soles of the feet. The palms and/or soles become red and scaly, with white/yellow sterile pustules (blisters of non-infectious pus). Reddish-brown patches are present as the pustules resolve. Psoriasis affecting the palms and soles can severely limit everyday activities.
  8. Acrodermatitis of Hallopeau is a rare form of pustular psoriasis that can affect the fingers, toes and nails. This can also be very painful and debilitating form of psoriasis.

Though uncommon, certain forms of psoriasis require urgent medical attention:

  • 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 medication.
  • Erythrodermic psoriasis describes instances where almost the entire body surface is involved, and is characterised by red skin with diffuse, fine, peeling scale. It is quite rare, generally occurring in those who have unstable plaque psoriasis.

Scalp psoriasis

Nail psoriasis

Guttate psoriasis

Pustular psoriasis

Plaque Psoriasis (psoriasis vulgaris)

How is psoriasis diagnosed?

Most cases of psoriasis are diagnosed by family doctor (a general practitioner/GP), who is usually best placed to give advice on how to manage and treat your condition; sometimes however onward referral to a consultant dermatologist may be necessary.

Whether you see your family doctor  or a hospital-based dermatology team (which includes consultant doctors and nurses), you may have been thinking about your appointment, including what you would like to discuss with your doctor or nurse. There can be a lot to consider or remember.

Time with a GP or your hospital dermatology team is precious, so how can you make the most of your time?

To help you with this, the ISF have developed two step-by-step guides; one for Family doctor/GP visits and a second for Hospital visits about your psoriasis.  These can help you to prepare for your next appointment, find our guides on our resources page


Family Doctor / GP and Hospital Visits Guides

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.

How is psoriasis treated?

The good news is that there is a range of treatment options available, as well as on-going research examining potential new treatments. The treatment of psoriasis depends on its severity and location.

Talk with your doctor to find a treatment regimen that is most appropriate for you. Try not to become disillusioned if one treatment does not work; psoriasis can sometimes be challenging condition to treat as no single medication is effective for everyone affected.

Your doctor may prescribe several different treatments before finding one that works for you. This is usually done in a step-by-step process.

Be sure to talk to your doctor about your symptoms and progress, and if necessary alternative treatment options or onward referral to a consultant dermatologist.

Treatment options

  1. Topical treatments – creams or ointments applied directly to the skin
    Phototherapy – is a form of artificial ultraviolet light, delivered in hospital dermatology departments
  2. Systemic treatments – medicines that work throughout the body. They may come in the form of a liquid, tablet or injection.
  3. Biologic treatments – are targeted medicines used to inhibit part of the immune system that drive inflammation. These are mainly injections but some are now being developed in tablet form.

The use of emollients and soap substitutes also form an integral part of treatment.

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

Measuring the impact of your condition

Psoriasis affects people in different ways. Living with psoriasis can affect you emotionally and socially, as well as physically. Psoriasis can vary in severity in the same person at different times. The unpredictable nature and the visibility of psoriasis can negatively impact on a person’s quality of life and personal relationships.

The Dermatology Life Quality Index (DLQI) is a questionnaire that your doctor may ask you to fill out. It helps the doctor assess the impact psoriasis is having on a person’s life, physically, emotionally, socially and sexually. It also assists the doctor to measure how well treatment is working.

If you are feeling anxious or down, it is important to share your feelings with your doctor.

General psoriasis skin-care tips

  • 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 – Many people who have psoriasis find that sunlight can help their skin to clear. However, being sensible in the sun is important and sunburn must be avoided at all times. While sunburn is a risk for skin cancer, it can also bring about the Koebner phenomenon – this is where psoriasis can develop at the site of an injury, such as a burn. Remember the five ‘Ss’ of sun safety – Seek shade, Slip on clothing and cover skin as much as possible, Slap on a hat with a wide brim, Slop on broad-spectrum (UVA/UVB) with a sun protection factor (SPF) of at least 30+ for adults and 50+ for children, Slide on sunglasses.

General health and self-care tips

The following general measures may also be very helpful in the management of psoriasis, for more information please consult our booklet, What you need to know about Psoriasis.

  • Stop smoking, but we know that this is easier said than done!
  • Maintain a healthy weight
  • Eat a healthy diet
  • Have your ‘risk factors’ checked
  • Exercise, even a short brisk walk is a great start

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, joint stiffness and potential damage to joints, but can be treated.


PsA is less common than other forms of arthritis such as rheumatoid arthritis.

What causes PsA?

PsA is an autoimmune disease, occurring 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 in those who are susceptible.

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 with PsA

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).
  • 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.

Treatment of PsA

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.

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

Additional support and guidance is available from Arthritis Ireland.

Some points to remember about psoriasis

  1. It is a chronic, systemic, inflammatory skin disease.
  2. It is related to the immune system – an autoimmune disease.
  3. It may run in families (there are several different genes involved in psoriasis).
  4. It is not curable, but there are a range of effective treatment options available.
  5. It is not contagious.
  6. It is sometimes associated with psoriatic arthritis.
  7. It is associated with a slightly higher risk of diabetes, high blood pressure, high cholesterol and obesity.
  8. It is associated with a slightly higher risk of cardiovascular disease (angina, heart attack and stroke).
  9. There is a strong association between psoriasis and depression.

ISF psoriasis videos

Videos about psoriatic disease (psoriasis and psoriatic arthritis) recorded at the Irish Skin Foundation’s (ISF) skin health event, SkinSideOut on 22 April 2023 are available to view below. 

Psoriasis in 2023

‘Psoriasis in 2023’, presented by Prof Brian Kirby, Consultant Dermatologist, St Vincent’s University Hospital; and Full Clinical Professor, Charles Institute of Dermatology, University College Dublin, Ireland.

Psoriasis Panel Discussion

Panel discussion on psoriasis with Prof Brian Kirby, Consultant Dermatologist, St Vincent’s University Hospital; Dr Carl Orr, Consultant Rheumatologist, St Vincent’s University Hospital; and former ISF board member, Caroline Irwin, who has been living with psoriasis for over 50 years.

Scalp Psoriasis

Scalp Psoriasis talk and ‘How to’ session, presented by Carmel Blake, Advanced Nurse Practitioner in Dermatology and Clinical Manager of the ISF Ask-a-Nurse Helpline.

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