L. Guenther, MD, FRCPC
University of Western Ontario, London, Ontario, Canada
Psoriasis vulgaris is an autoimmune disease with genetic linkages (e.g., HLA-Cw6). Approximately 1/3 of patients have a relative with psoriasis. Activation of T-cells and TH1 cytokines result in epidermal hyperproliferation, reduction of epidermal differentiation, and inflammation.
Impact on the Sufferer
Psoriasis has a significant impact on quality of life.
- In one study in which several diseases were compared, only depression had a greater mental impact, and congestive heart failure a greater physical impact.[Rapp SR, et al. J Am Acad Dermatol 41:401-7 (1999).]
- A 2003 survey by the Psoriasis Society of Canada (n=1,108) reported a significant impact on work, school, and leisure pastimes in 81% of respondents.
- A 1998 US National Psoriasis Foundation survey of 17,488 members noted that 40% had trouble receiving service in establishments such as hair salons, pools, and health clubs, and >50% had incorrectly had their disease classified as contagious. [Krueger G, et al. Arch Dermatol 137:280-4 (2001).] Of the respondents ages 18-34 years:
– 81% felt embarrassed
– 75% felt they were unattractive
– 54% suffered from depression
– 10% had contemplated suicide.
Diagnostic Features of Psoriasis Vulgaris
- Red, scaly plaques, which are often very itchy and may bleed when scratched.
- The elbows, knees, lumbo-sacral area, and scalp are commonly involved, although any part of the skin may be affected, including the palms and soles.
- Involvement may be extensive.
- It is chronic with remissions and exacerbations.
- Concomitant nail changes are common (pitting, onycholysis, oil drop changes, subungual hyperkeratosis, and nail plate thickening).
- ~30% may have psoriatic arthritis.
Treatment depends on:
- disease extent
- location of plaques
- response to previous treatment
- other medical conditions
- concomitant medications
- proximity to medical resources
- patient preference.
Topical therapy is the most widely used treatment and usually the first step, particularly in patients with < 10% total body involvement. In patients with more widespread disease, it is often used as adjunctive therapy for resistant plaques, plaques in visible areas, and pruritic lesions.
Phototherapy, traditional systemic treatment (e.g., methotrexate, cyclosporine, acitretin (Soriatane®) and biologic agents (e.g., alefacept (Amevive®), efalizumab (Raptiva®), etanercept (Enbrel®)) are used to treat widespread or resistant disease.
General Skin Care
- Avoid injury to the skin (e.g., scratching) since this may induce psoriasis in the area of injury, i.e., the “Koebner phenomenon”.
- Mild cleansers and tepid water should be used for cleansing.
- Moisturizers minimize scaling, painful fissuring, and itching. They should be applied immediately after bathing. Application of moisturizers in the direction of the patient’s hair minimizes the risk of folliculitis.
**Avoid Aggravating Medications**
In some patients, beta-blockers, ACE inhibitors, antimalarials, nonsteroidal anti-inflammatory drugs (NSAIDs) and lithium may aggravate the disease or make it more resistant to treatment. In some patients, it may take up to 1 year of use before the aggravating effects are seen.
- Salicylic acid is keratolytic and increases the penetration of topical corticosteroids. It decreases scaling which may be particularly thick on the palms, soles, and scalp.
- Urea may also decrease scaling on the palms and soles.
- Tar bath oils, creams, lotions and ointments may relieve itching and reduce plaques.
- Over-the-counter treatments are applied once or twice daily.
- Use is limited by the smell, and potential to stain, irritate, and induce folliculitis.
- Hydrocortisone cream may be helpful for facial and fold psoriasis; however, a stronger topical corticosteroid is usually required elsewhere.
- Relieva®, a Mahonia aquifolium extract, is anti-inflammatory and decreases keratinocyte hyperproliferation. Statistically significant improvement in the signs and symptoms of mild-to-moderate psoriasis has been noted in clinical trials.
- Liquid bandaid helps “seal” fissures, thereby decreasing pain and allowing healing to occur.
- Shampoos containing tar, salicylic acid, zinc pyrithione, ketoconazole and many “dandruff” shampoos may decrease scalp scaling.
- Oral antihistamines may improve itching; nonsedating ones are generally used during the day and sedating ones at bedtime.
Prescribed Topical Agents
Compounding should be avoided if possible, since the stability of the resultant product is unknown. In contrast, commercially manufactured fixed combination products have been tested for stability. Some products work better in an acid base (e.g., topical steroids), whereas others (e.g., calcipotriol) are more effective in an alkaline base. Mixing a commercially available steroid such as betamethasone dipropionate (Diprosone®) with calcipotriol (Dovonex®) results in rapid degradation of both active ingredients. In contrast, Dovobet®, a commercially available product containing both ingredients, provides a base in which both products are stable.
- Most widely prescribed treatment.
- Available in low, medium, high, and ultra-high potency.
- The steroid with the lowest effective potency should be used, particularly on the face and skin folds.
- On the palms and soles, more potent steroids are usually required.
- Lotions and gels are commonly used on the scalp.
- Creams and ointments are used elsewhere.
- Ointments are often more potent than creams
- Steroids are safe short-term and intermittently long-term treatments.
- Once daily application is often as efficacious as twice daily.
- Use 2-3 times/wk may maintain remission.
- Adverse effects include:- atrophy
– striae (particularly in intertriginous areas)
– perioral dermatitis
– contact sensitization (to the steroid itself as well as to the base and preservatives)
– tachyphylaxis (lack of effect with continued use)
– flare upon discontinuation
– adrenal suppression (don’t use >50 mg of ultra high potency steroids/wk).
Topical Calcipotriol (Dovonex®)
- Used twice daily to achieve control and one or twice daily for long-term maintenance.
- Speed of onset is slower than with topical steroids, but rebound is not associated.
- Use 100g/wk maximum to minimize the risk of hypercalcemia.
- Cream and ointment is used for trunk and limbs.
- Solution is used for the scalp.
- Commonly used in combination with a mid, high, or superpotent topical steroid (a.m./p.m. regimen).
- Weekday calcipotriol with weekend superpotent topical corticosteroid (e.g., Ultravate®) may maintain improvement.
- Synergistic with:- topical corticosteroids
– phototherapy [ultraviolet B (UVB), psoralen + ultraviolet A (PUVA)]
- Adverse effects:- irritation (usually mild and rarely results in discontinuation)
– facial dermatitis.
Topical Calcipotriol and Betamethasone Dipropionate (Dovobet®)
- Contains calcipotriol and betamethasone dipropionate in the same concentrations as Dovonex® and Diprosone®, respectively.
- Applied once daily.
- More efficacious than its individual components with a faster onset.
- After 4 weeks of treatment, ~50% are clear or almost clear.
- Similar cutaneous adverse events to betamethasone dipropionate and ~ half that of calcipotriol.
- After control is achieved with Dovobet®, remissions may be maintained with either calcipotriol monotherapy or calcipotriol on weekdays and Dovobet® on weekends.
Topical Tazarotene (Tazorac®)
- Selective retinoid.
- Usually used once daily in combination with a mid or high potency steroid.
- Improvement may be maintained with Mon/Wed/Fri tazarotene and Tues/Thurs clobetasol ointment.
- Synergistic with:- topical cortosteroids
– phototherapy (UVB, PUVA).
- Contraindicated in pregnancy.
- Topical retinoids thin the stratum corneum which may allow more penetration of ultraviolet radiation into the skin and result in a lower threshold for sunburn
- Irritation limits its use.
Topical Calcineurin Inhibitors
- Topical pimecrolimus (Elidel®‚ 1% cream) and tacrolimus (Protopic®‚ 0.03% and 0.1% ointment) are efficacious for facial and intertriginous psoriasis.
- Applied twice daily.
- Do not cause skin atrophy.
- May cause burning or stinging, particularly during the first couple of weeks of therapy and when the patient is exposed to heat.
- Sun protection is recommended because of the theoretical risk of skin cancer. However, no studies have shown photosensitivity with calcineurin inhibitors.
- Health Canada issued a Health Advisory in April 2005 informing healthcare providers and patients about safety information from studies of animals given very high doses of these drugs indicating a potential cancer risk.
- These drugs are indicated for nonimmunocompromised patients 2 years of age and older.