Key points:

  • The consensus among researchers suggests psoriasis arises from the interaction of multiple genes, immune dysfunction and environmental factors
  • Elderly patients may be less likely than younger people to bring the condition to their doctors’ attention.
  • Psoriasis is not a geriatric disease per se. Nevertheless, this common skin disease imposes an increasingly heavy burden on middle-aged and elderly patients.

Around 1.2 million people in the UK suffer from psoriasis1 and with the ageing of the population, it is becoming increasingly widespread among the middle-aged and elderly. Any one of the several types of psoriasis (see Table 1) can undermine health-related quality of life (HRQoL) at any age. However, the psychological burden and HRQoL impact may be even greater among the elderly2.

Beneath the surface

While the primary cause remains unknown3, the consensus among researchers suggests that psoriasis arises from the interaction of multiple genes, immune dysfunction and environmental factors4. Several lines of evidence support this model. For example:

  • about 30 per cent of patients have a first-degree relative who suffers from the disease5 and psoriasis seems more common among Caucasians than in other ethnic groups6, both of which implicate genetic factors;
  • numerous environmental factors trigger or exacerbate psoriasis, including stress, infections, trauma (Koebner phenomenon)5 and certain medications (including some widely used by elderly people such as betablockers3, NSAIDs5 and ACE inhibitors3).

Psoriasis seems to arise when an environmental factor interacts with the inherited predisposition to activate helper Thelper1 (Th 1) lymphocytes. The Th 1 cells release cytokines that stimulate keratinocyte proliferation and increase expression of adhesion molecules in blood vessels supplying the skin. In turn, the adhesion molecules augment cytokine production by Th 1 lymphocytes, further promoting keratinocyte proliferation5 and increasing epidermal turnover.

This immunological cycle means chronic plaque psoriasis begins as papules, which coalesce into well demarcated plaques. The lesions bleed if the silvery scale is removed (Auspitz sign) and over 80 per cent of patients report itch, which seems to have a complex aetiology, including increased levels of mast cells, substance P and nerve growth factor (NGF)7. Elbows and knees are the most common sites affected, although many patients develop lesions on their lower back, scalp or nails. Older patients (and others with a long duration of disease, those with extensive involvement or psoriatic arthritis) are especially prone to develop nail psoriasis5. While rarely the presenting symptom, nail psoriasis may be confused with onychomycosis, another disease common in the elderly8 .

A common condition

Between 1.5 per cent4 and two per cent6 of the UK population suffers from psoriasis. Men and women seem to be equally likely to develop the condition6. The age of onset peaks twice, once in the late teens and again in the late 50s5 . The prevalence declines by 28 per cent and 60 per cent between 70–79 years and 80–89 years respectively, compared with 60–69 years. The prevalence then falls to 47 per 10,000 in patients 90 years or over4. A recent analysis reported that 24 per cent of UK psoriasis patients were more than 65 years old1. The decline may suggest psoriasis goes into remission, that elderly patients may be less likely than younger people to bring the condition to their doctors’ attention or both4. In a recent study, 45 per cent of patients said they had not consulted their doctor about their psoriasis in the preceding year1. Several factors could contribute to this low consultation rate including decreasing concerns about physical appearance9, poor previous experiences with treatments and low expectation of success1.

Emotional and physical consequences

Psoriasis is not commonly fatal. Erythrodermic psoriasis can be fatal, but this is rare. Nevertheless elderly people may be at higher risk of mortality due to co-morbidities or adverse events4. Psoriasis is, for example, associated with an increased risk of non-melanoma skin cancer and lymphoma, especially in patients with more severe disease. It is unclear, however, whether this association arises from the disease, a side effect or both5.

Other complications include psoriatic arthritis, which tends to be asymmetric and affects fi ngers and toes. Between five per cent and seven per cent of people with psoriasis develop psoriatic arthritis, although the prevalence reaches around 40 per cent in patients with extensive disease6. Depression, anxiety and sexual problems are also common. Indeed, some patients with psoriasis show suicidal ideation. However, the association with severity is not linear — psychological problems may emerge among people with, objectively, less severe disease5.

As these examples of the psychological burden suggest, psoriasis can markedly undermine HRQoL. Indeed, the impact is similar to other chronic diseases experienced by the elderly such as depression, myocardial infarction, hypertension, congestive heart failure or type 2 diabetes6 . Despite the decline in prevalence, there is no evidence that the impact on HRQoL lessens with advancing age. In a post hoc analysis assessing etanercept, no statistically significant differences emerged in the Dermatology Life Quality Index (DLQI) scores between elderly and young patients10.

Indeed, psoriasis may impose a greater burden on elderly people, according to a study of 936 patients hospitalised with the condition. Patients aged 65 years or older reported a greater impairment in their HRQoL than those less than 65 years of age on all domains of the Skindex-29 scale. (This scale is a reliable and valid self administered instrument designed for measuring health related quality of life in dermatology. It consists of 29 items loading on three scales to measure the effects of skin conditions on symptoms, emotional state and social functioning. The questions refer to the previous four week period and scores are given on a five-point scale from ‘never’ to ‘all time high’. Higher scores indicate poorer quality of life.) Furthermore, older patients endured greater psychological distress. Older women, suffering from concurrent anxiety and depression showed the worst HRQoL2 .

While the potentially profound impact of psoriasis on HRQoL is well established, few studies examine whether this changes over time. However, one recent study examined HRQoL during an 11-year follow-up using the Impact of Psoriasis Questionnaire (IPSO). The impact on most social determinants of HRQoL remained stable. In contrast, concerns about physical appearance decreased and mean IPSO scores declined by a fifth. Furthermore, the proportion of patients in whom psoriasis seems to have a low overall impact on HRQoL increased from 43 per cent at baseline to 53 per cent after 11 years. The improvement was especially marked in patients reporting poor health, where the mean increase was around three times greater than among those in good health9. These studies suggest that while some patients adapt to suffering from their disease, psoriasis undermines psychological well-being and HRQoL at all ages.

Psoriasis imposes a heavy economic burden. Sixty per cent of UK patients with severe psoriasis took time off work in the previous year because of their condition. Furthermore, people with severe disease may require one or more hospitalisations each year. Each stay lasts for an average of 20 days and inpatient care costs, excluding drugs, total around £5,215 for each person6. During 2003, doctors wrote nearly one million prescriptions for psoriasis therapies, which cost £27.8m. This excludes treatments used for other conditions (eg, corticosteroids or methotrexate) as well as costs arising from secondary and tertiary care6 and so markedly underestimates the cost. Clearly, optimising outcomes is important to limit the economic burden.

Primary care management

Clinicians need to counsel patients that psoriasis is incurable and ensure sufferers focus on improvements, rather than clearance. As only between 25 per cent and 30 per cent of patients have moderate (three to 10 per cent of body surface area) to severe psoriasis (>10 per cent)1, topical agents are the first-line treatment. GPs should also encourage patients to use emollients. However, patients should avoid emollients and other products containing lactic acid or alphahydroxy acid, which may irritate inflamed or broken skin3.

Numerous studies show topical steroids (including betamethasone11, mometasone12 and clobetasol13) improve psoriasis. Indeed, doctors issued steroids to around 61 per cent of UK patients. Corticosteroid combinations and topical vitamin D analogues were each used by around 40 per cent of patients respectively. Just one in 50 patients used a systemic agent4. The widespread use of steroids is testament to their efficacy and tolerability, although side effects may include skin atrophy, striae and tachyphylaxis, if they are used inappropriately5. Concerns about side effects may lead some patients and physicians under-dosing with topical steroids. However, as there is more understanding as to their nature, topical steroids are now available in a variety of potencies, strengths and formulations. This allows clinicians to tailor treatment according to the patient as well as differences in the sensitivity and thickness of the skin.

Vitamin D derivatives (eg, calcipotriol) normalise keratinocyte proliferation and differentiation. Calcipotriol is as effective as potent topical steroids, but may cause pruritus or burning5. Hypercalcaemia is unlikely when used according to the label. Most reports of hypercalcaemia occurred in patients who received prolonged treatment with 200g or more weekly3. The main side effect is irritation around the lesion, although few patients cease treatment as a result. Against this background combination therapy offers several benefits:

  • used as a combination therapy, steroids and calcipotriol are more effective than either agent used alone5;
  • steroid lessens the irritation associated with calcipotriol;
  • steroids act rapidly; calcipotriol may take up to six to eight weeks for full effects to emerge3;
  • applying topical treatments may be messy and time consuming, which may compromise compliance1;
  • using one formulation rather than two obviously reduces the time and mess.

Several formulations are available, including calcipotriol plus betamethasone dipropionate, which an analysis of UK prescribing habits found accounted for 41 per cent and 28 per cent of psoriasis scrips respectively1. Calcipotriol plus betamethasone is a once daily treatment and can be used for up to four weeks, repeat courses can then be prescribed, if deemed suitable by the healthcare professional. If adequate doses of calcipotriol and steroids used in combination fail to produce an adequate response, patients may benefit from a trial of one or more topical therapies:

  • topical retinoids (eg, tazarotene) normalises keratinocyte proliferation and differentiation;
  • tazarotene appears to be as effective as topical steroids, although there are no direct comparisons with calcipotriol; side effects include skin irritation, pruritus, burning, stinging, erythema, desquamation and teratogenicity; adverse effects appear to be more common with tazarotene than calcipotriol5;
  • topical immunosuppressants (eg tacrolimus) inhibit T-lymphocytes; adverse events include burning, stinging, pruritus, influenza-like symptoms, erythema, acne and folliculitis — some reports link topical immunosuppressants to skin cancer and lymphoma, however studies need to ascertain if the link is causal5;
  • anthralin normalises keratinocyte proliferation; side effects include skin irritation, erythema, staining of skin and clothing, and odour;
  • coal tar is keratolytic, anti-inflammatory and antiproliferative; side effects include skin irritation, folliculitis, odour and staining of clothing.

It has been suggested that neither coal tar nor anthralin is more efficacious than calcipotriol5. Despite these limitations, a quarter of UK patients use coal tar4 .

Phototherapy

Patients in whom the psoriasis involves more than 20 per cent of their body or who do not respond to topical therapy may benefit from UVB phototherapy and PUVA (a combination of the photosensitiser psoralen and UVA)5. To reduce the risk of skin cancer, the British Association of Dermatologists (BAD) guidelines (http://www.bad.org.uk/healthcare/guidelines/) suggest that patients should receive no more than 150 PUVA treatments over their lifetime. Furthermore, the need to visit a specialist centre two or three times a week can impose a significant time burden1. Elderly people may also face transportation problems.

Systemic treatments The BAD guidelines suggest using systemic therapies in the following circumstances:

  • failure of an adequate trial of topical therapy;
  • repeated hospital admissions for topical therapy;
  • extensive chronic plaque psoriasis in the elderly or infirm;
  • generalised pustular or erythrodermic psoriasis;
  • severe psoriatic arthropathy.

In general, the BAD guidelines note, systemic therapy is appropriate when more than 10 per cent of the body surface area, the Psoriasis Area and Severity Index (PASI) score is greater than 10 or the DLQI is greater than 10.

References 

  1. Gillard SE, Finlay AY. Current management of psoriasis in the United Kingdom: patterns of prescribing and resource use in primary care. Int J Clin Pract 2005;59:1260-7
  2. Sampogna F, Chren MM, Melchi CF, et al. Age, gender, quality of life and psychological distress in patients hospitalized with psoriasis. Br J Dermatol 2006;154:325-31
  3. Pardasani AG, Feldman SR , Clark AR. Treatment of Psoriasis: An Algorithm-Based Approach for Primary Care Physicians. Am Fam Physician 2000;61:725-33
  4. Gelfand JM, Weinstein R, Porter SB, et al. Prevalence and treatment of psoriasis in the United Kingdom: a population-based study. Arch Dermatol 2005;141:1537-41
  5. Luba KM, Stulberg DL. Chronic plaque psoriasis. Am Fam Physician 2006;73:636-44
  6. NICE. Etanercept and efalizumab for the treatment of adults with psoriasis. London: National Institute for Health and Clinical Excellence, 2006.
  7. Nakamura M, Toyoda M, Morohashi M. Pruritogenic mediators in psoriasis vulgaris: comparative evaluation of itchassociated cutaneous factors. Br J Dermatol J Dermatol 2003;149:718-30
  8. Elewski BE. Onychomycosis: pathogenesis, diagnosis, and management. Clin Microbiol Rev 1998;11:415-29
  9. Unaeze J, Nijsten T, Murphy A, et al. Impact of psoriasis on health-related quality of life decreases over time: an 11-year prospective study. J Invest Dermatol Dermatol 2006;126:1480-9
  10. Militello G, Xia A, Stevens SR, Van Voorhees AS. Etanercept for the treatment of psoriasis in the elderly. J Am Acad Dermatol 2006; 55:517-9
  11. Flammiger A, Maibach H. Drug dosage in the elderly: dermatological drugs. Drugs Aging 2006;23:203-15
  12. Griffiths CE, Taylor H, Collins SI, et al. The impact of psoriasis guidelines on appropriateness of referral from primary to secondary care: a randomized controlled trial. Br J Dermatol 2006;155:393-400