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Psoriasis is a chronic, debilitating, inflammatory skin disease, characterised by an accelerated rate of turnover of the top layer of the skin.
Although it is a chronic condition, its course may be variable, with flare-ups and remissions. The cause of psoriasis is not fully understood but evidence suggests that there is a strong genetic component and that environmental factors also play a role, such as emotional stress or infection, which may trigger the first episode of psoriasis or exacerbations.
Psoriasis is one of the most common skin diseases in Ireland and affects at least 73,000 people, 20 per cent of whom will require secondary care, according to international standards.
Psoriasis can occur on any part of the body, but is most commonly found on the elbows, knees, lower back and scalp (seborrhoeic psoriasis). It can also affect the fingernails and toenails.
Triggers 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. It can occur on various parts of the body, including the scalp, elbows, and or knees.
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) — are also a classic symptom.
Appearance and sites
Plaque psoriasis is the most common form of psoriasis, affecting approximately 90 per cent 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.
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.
Guttate psoriasis 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.
Flexural psoriasis occurs 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. A yeast-like fungal infection (candida albicans) can also develop, due to the naturally warm moist environment found in these areas.
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.
The scalp is one of the most common sites to be affected by psoriasis (see image below), 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 fine white flakes (similar to dandruff) or the scale may become thickened, with an appearance like cradle cap.
Psoriasis may also affect the face, particularly around the hairline.
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 localised pustular psoriasis. The palms and/or soles become red and scaly, with white/yellow sterile pustules. The pus consists of white blood cells. Reddish-brown patches are present as the pustules resolve. Psoriasis affecting the palms and soles can severely limit everyday activities.
Generalised pustular psoriasis is extremely rare. It can occur on any part of the body and is characterised 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.
Psoriasis and working life
Psoriasis affects the working life of many people. Having psoriasis can affect career choices, result in absenteeism or unemployment, decrease work productivity, and lead to stigmatisation in the workplace. Work-related stress can contribute to exacerbations of psoriasis, while having psoriasis can increase stress at work.
Coping with psoriasis and/or PsA at work can be very challenging. A 2014 survey by the US National Psoriasis Foundation found that 5-10 per cent of people with psoriasis said that their disease had affected their career pathway, by turning down a promotion or leaving a job. This was higher still in patients who had joint involvement, with 12 per cent turning down a promotion because of their psoriatic arthritis, and 21 per cent leaving their job. Several studies have also shown that psoriasis can result in reduced productivity on the job. Studies of PsA patients show a 35-46 per cent decrease in work productivity due to the impact of their disease.
Psoriasis can be embarrassing. The reaction of colleagues, particularly those with little knowledge about psoriasis who think psoriasis is an infection or contagious, can be demoralising and stigmatising. The scales and flakes, which can be visible on work suits, on desktops and other work areas, can be distressing and humiliating. The psychological impact of psoriasis can be immense — psoriasis patients have higher rates of depression and anxiety, which in turn can affect work performance.
Successful treatment of psoriasis and PsA can have a dramatic impact on quality of life at work and on work productivity. According to multiple studies, patients taking biologic treatments for their psoriasis may experience an improvement in their work performance alongside the improvement of their disease. Studies have shown 60-67 per cent reductions in work productivity loss with biological treatments. Another study showed a 30 per cent improvement in presenteeism in patients with PsA treated with TNF inhibitors.
It is important for patients not to feel alone if they struggle to deal with their psoriasis in the workplace. The US National Psoriasis Foundation has some helpful tips to help patients cope with psoriasis and/or PsA at work: www.psoriasis.org/advance/working-psoriasis.
Dr Caitriona Ryan, Consultant Dermatologist, St Vincent’s Private Hospital, Dublin. www.caitrionaryandermatology.ie
Psoriatic arthritis (PsA) is a chronic, inflammatory form of arthritis associated with psoriasis that can cause pain, swelling and damage to joints.
The prevalence of PsA is estimated to be between 0.3-1 per cent of the general population. However, studies have indicated that up to 42 per cent 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.
For the majority of patients, psoriasis develops first, commonly around 10 years before PsA. Joint problems start before psoriasis in approximately 16 per cent of patients, while 15 per cent 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 psoriatic arthritis:
Joint pain, especially with redness, swelling and tenderness.
Pain in the heel(s) or tennis elbow.
A finger or toe that is completely swollen (sausage-shaped) and painful for no apparent reason.
Morning stiffness/pain in the back that improves with movement
A screening tool for PsA called the ‘Psoriasis Epidemiology Screening Tool’ (PEST) can help 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.
Potential psoriasis triggers
Certain medications, such as lithium, beta-blockers, and anti-malarials, have been reported to aggravate psoriasis symptoms. Stopping some medicines abruptly can also lead to flare-ups.
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 is also important. 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. Psoriasis may improve by limiting alcohol intake, giving up smoking and maintaining a healthy weight. Exercise should be advised to relieve stress and to reduce weight.
Facts on psoriasis
It is a chronic, systemic, inflammatory skin disease.
It may run in families (there are several different genes involved in psoriasis).
It is not curable, but treatments are available.
It is sometimes associated with psoriatic arthritis.
It is associated with a slightly higher risk of diabetes, high blood pressure, high cholesterol and obesity.
It is also associated with a slightly higher risk of cardiovascular disease (angina, heart attack and stroke).
There is a strong association between psoriasis and depression.
Source: Irish Skin Foundation
The long-established dithranol is an extremely effective and safe treatment for chronic plaque psoriasis. Early research found it cleared 95 per cent of suitable patients and the average remission is six months when used as an inpatient treatment.
Its main disadvantage is that it stains the skin (temporarily) and clothes (permanently). It can also burn normal skin, so must be very carefully applied to the plaques only. It is started with a low concentration and the strength is gradually increased.
Tar is also an extremely effective treatment, but it is very messy to do in the home setting.
A key treatment currently for moderate-to-severe disease is ultraviolet therapy — UVB phototherapy.
It may be used alone, eg, in widespread, thin-plaque psoriasis, or more commonly in conjunction with inpatient or outpatient topical therapy.
Narrow-band UVB is the current wavelength of choice, which has been shown to clear the vast majority of patients, with an average remission of six months.
Some patients achieve prolonged remission on this treatment, though limited access and needing to attend a clinic three times weekly when receiving the therapy is time-consuming for patients.
PUVA therapy is also beneficial, which is a type of phototherapy that combines the oral or topical photosensitising chemical psoralen and exposure to increasing doses of UVA. This has similar success rates to UVB phototherapy and patients attend a clinic twice weekly.
For those with moderate- to-severe psoriasis who have not responded to milder treatments, systemic treatment may be needed.
Some examples are ciclosporin, methotrexate, acitretin and fumaric acid esters. These drugs affect the underlying cause of psoriasis – a malfunctioning immune system that causes inflammation, and an increase in the rate at which skin cells are produced and shed from the skin (approximately four times faster than normal).
A number of biologic agents have been licenced for the treatment of psoriasis, including TNF inhibitors (eg adalimumab, etanercept and infliximab), the interleukin (IL) 12/23 compound ustekinumab, and the IL-17A antagonist, secukinumab. These agents have significantly broadened the range and efficacy of treatment options available and revolutionised the care of more severe psoriasis patients.
Last year the HSE approved the reimbursement of ixekizumab (a humanised, anti-IL-17 monoclonal antibody), for the treatment of moderate to severe plaque psoriasis in adults who are candidates for systemic therapy, providing another important treatment option.
This new wave of improved, targeted therapies heralds a new era in the treatment of psoriasis, according to the Irish Skin Foundation.
Resources on psoriasis
The Irish Skin Foundation provides support for both patients and healthcare professionals working in the field of dermatology. It operates a patient helpline, provides up-to-date specialist guidance, runs events for healthcare professionals and patients, as well as awareness campaigns and engages in advocacy for people with skin conditions. Its website provides useful guidance on psoriasis, and information booklets for patients can be downloaded or requested in hardcopy form.
This year World Psoriasis Day takes place on 21 October. The Irish Skin Foundation National Psoriasis Meet-Up will take place in the Tower Hotel, Waterford, supported by AbbVie and Novartis, on 29 October 2017.