#10: Psoriasis


Mum brings two of her twelve children to see you for routine physical exams.  You finish early and are amazed that neither of them have rashes, although their health has been steadily improving since they offed the cats. 

Mum mentions that her Dad is visiting from Canada , is in the waiting room, and needs a prescription refill.  He has been complaining that his nail condition has recurred.  He was seen “…about two years ago” and was treated with “…some pills” that resulted in good resolution of his symptoms “…although it took a hell of a long time”.  He remembers that the doctor did “…some nail test” but doesn’t recall the result.  He proudly shows you the picture he keeps in his wallet of his hands before and after treatment.

Grandad excuses himself to go to the bathroom and Mum takes the opportunity to tell you that she is concerned about his drinking.  She says that he gets “…pretty boozy” with the beginning of hockey season, and in fact, celebrated the Canuck’s 4-0 win over the Sabres by getting “…blitzed” on Labbatt Blue.

KOH prep of nail scrapings is negative.  A fungal culture will return in about four weeks.

What is this?  Psoriasis of the nails.  Hints: for those of you with 20/6 vision, there are characteristic skin changes.  Also note the sausage fingers that might represent changes of psoriatic arthritis.  Occasionally nail changes occur in patients who have no evidence of cutaneous involvement, although the skin rash may appear years later.

          There are three main types of abnormality:

1.      Pitting

2.      Onycholysis

3.      Gross psoriatic nail dystrophy (pictured): This type is secondary to psoriasis underneath the posterior nail fold and the lunula in the nail matrix.  The nail lacks luster, becomes opaque, thickened and discoloured.  Symmetry distinguishes this type from the fungal disorders, as all the nails are usually involved to some degree; but the situation is not static, with one nail recovering and then another deteriorating.

Did he catch it from the kids?  Nope

How is it diagnosed?  It is always worth taking clippings for mycological examination because patients with psoriasis can also have fungal infections.

How is it treated?  Difficult to treat.  Powerful topical steroids, in the form of scalp application  applied under the nail, may be tried for onycholytic disorders.  Matrix disorders do not respond to topical therapy but they do return to normality during systemic therapy with methotrexate or etretinate, when this is given for extensive cutaneous disease.  However, it is questionable whether systemic treatment is justified for nail involvement only.

Are any blood tests indicated?  Well, lets see…how about some LFT’s for the old boozer.  A CBC with diff is also worth thinking about if one is considering MTX.

Are you comfortable refilling his prescription?  I would decline using careful patient centered language.  I would then inquire as to what was up in his life.

What does the evidence suggest is the most effective therapy? The traditional therapy for nail psoriasis is intralesional corticosteroid injection given monthly. Potent topical corticosteroids also have been used to treat periungual and nail plate psoriasis but have proven to be unsatisfactory. Because of the chronic nature of the disease and the need for repeated application of corticosteroids, adverse events have occurred ranging from nail fold atrophy and telangiectasia to atrophy of the underlying phalanx, the complication known as "disappearing digit." Other treatments include photochemotherapy, 1% 5-fluorouracil cream, irradiation, oral retinoids, methotrexate, and cyclosporine.  Because of the need for a consistently effective therapeutic method, several recent clinical trials and case reports have investigated the safety and efficacy of the various treatments for psoriatic onychopathy. Although intralesional injection of triamcinolone

acetonide (2.5 to 3.0 mg) is the standard treatment used by many dermatologists, there are few formal clinical trials that examine this therapy. The efficacy of intralesional steroids for treatment of psoriatic nail dystrophy was evaluated by de Berker and Lawrence, who reported the clinical response of the following five features: subungual hyperkeratosis, pitting, onycholysis, transverse ridging, and nail plate thickening.  In contrast with the usual concentration of 2.5 to 3.0 mg/mL, these researchers administered triamcinolone acetonide at a concentration of 10 mg/mL to determine whether a simplified protocol had therapeutic value. Forty-six digits in 19 patients (12 men, 7 women, mean age 48 years) were injected with 0.1 mL triamcinolone acetonide (10 mg/mL) at each of four periungual sites: two at the nail matrix and one in each lateral nail fold directed medially towards the nail bed. This method was utilized to achieve delivery of the agent to both the nail matrix and nail bed. If needed, a second set of injections was administered after 2 months. Each patient received a mean of one to two doses, and follow-up ranged from 3 to 17 months.

The study found that intralesional steroid injections improved both nail bed and nail matrix abnormalities. Subungual hyperkeratosis responded in all the patients; ridging improved in 94%, and thickening improved in 83% of the patients. The common characteristics of pitting and onycholysis, however, improved in 45% to 50% of the patients. Complete resolution of onycholysis and pitting occurred in only 33% and 20% of the patients, respectively. The most common side effects included subungual hematoma and pain in the distal end of the injected digit. Within months, these adverse events all resolved. Difficulty with mobility of the distal interphalangeal joint, collagen atrophy, and rupture of the extensor tendon did not occur. The study observed that injection into the nail bed was effective in treating subungual hyperkeratosis and nail thickening. It also indicated that a stronger steroid solution (10 mg/mL) given less often may be as effective as a weaker solution (2.5 mg/mL) given more frequently.  Although this shorter, simplified approach offers an alternative to the standard monthly regimen, intralesional injections of triamcinolone acetonide at a concentration of 2.5 to 3.0 mg/mL remain the suggested practice.

Tazarotene, a novel acetylenic receptor-selective topical retinoid approved for the treatment of plaque psoriasis, is currently being investigated for the treatment of fingernail psoriasis. Tazarotene is a pro-drug whose metabolite, tazarotenic acid, binds with high affinity to the beta and gamma subtypes of retinoic acid receptors (RARs).  Retinoic acid receptor-gamma, the predominant type of RAR expressed in human epidermis, is a major mediator of retinoid action in the skin.  By interacting with these retinoic acid receptors, tazarotene modulates the three processes that occur in psoriasis: keratinocyte differentiation, keratinocyte proliferation, and inflammation.  Controlled clinical trials have demonstrated the efficacy of tazarotene 0.05% and 0.1% gels applied daily in treating mild to moderate plaque psoriasis, particularly in difficult-to-treat knee and elbow lesions.  Systemic side effects, phototoxic or photoallergic potential, and contact sensitization have not been reported; the most common adverse event has been mild to moderate local irritation.  At a recent symposium in New York City , Duvic presented a case of paronychial psoriasis of the hands that responded well to daily application of tazarotene gel.  Nail plate psoriasis, however, was not evaluated. Currently, at Columbia-Presbyterian Medical Center , a vehicle-controlled, double-blind, parallel, randomized study is being conducted to determine the safety and efficacy of tazarotene 0.1% gel applied both with and without occlusion to patients with fingernail psoriasis. As the results of this and other investigations become available, tazarotene may be added to the list of therapeutic agents used to treat nail plate psoriasis.

Calcipotriol, a second-generation synthetic analog of vitamin D3 , has been investigated for the treatment of nail psoriasis.  Controlled clinical trials have demonstrated that calcipotriol ointment is a safe and effective treatment for chronic plaque psoriasis.  Vitamin D receptors have been detected in most cell types in the skin, including keratinocytes, Langerhans' cells melanocytes, fibroblasts, endothelial cells, monocytes, and activated T cells.  Keratinocytes make 1,25(OH)2 D3 , contain 1,25(OH)2 D3 receptors, and respond to 1,25(OH)2 D3 with changes in proliferation and differentiation.  The best-explored action of 1,25(OH)2 D3 in the skin is to regulate differentiation, in part by regulating the calcium responsiveness of the keratinocyte.

Tosti et al conducted a double-blind, randomized study that compared the efficacy and safety of calcipotriol ointment with betamethasone diproprionate and salicylic acid in the treatment of nail bed psoriasis.  Twenty-nine

patients with fingernail psoriasis and 44 patients with toenail psoriasis applied either calcipotriol ointment, 50 mug/g, or betamethasone diproprionate, 64 mg/g, and salicylic acid, 0.03 g/g, to the affected nails twice daily for 3 to 5 months. After 5 months of treatment, subungual hyperkeratosis in fingernails was reduced by 49.2% in the group using calcipotriol and by 51.7% in the group using betamethasone diproprionate and salicylic acid. For toenails, the reductions in subungual hyperkeratosis were 40.7% and 51.9%, respectively, after 5 months of therapy. Topical calcipotriol was generally well-tolerated, and adverse reactions of erythema, periungual irritation, and burning at the application site each occurred in only three patients. This investigation indicated that calcipotriol is as effective a treatment as a topical steroid combined with salicylic acid and should be considered a safe alternative for treatment of chronic nail bed psoriasis.

Topical anthralin has been used to treat refractory nail psoriasis.  In Japan , Yamamoto et al treated 20 patients with psoriasis vulgaris with nail involvement. No patient had previously been treated with systemic immunosuppressive agents. Anthralin (0.4% to 2.0%) in petrolatum was applied to affected nail beds daily and washed away after 30 minutes. Ten percent triethanolamine was then applied to prevent pigmentation. It was reported that, after 5 months of treatment, 60% of patients demonstrated "fair" or "little" improvement, and 20% showed no response.  Onycholysis and subungual hyperkeratosis improved in all patients (7 of 7 and 4 of 4 patients, respectively), but the response was judged to be "fair" in approximately 50% of the patients and "little" in the other 50%. Of the eight patients with pitting, four had a "fair" response, three had "little," and one patient noted no response. Although few in number, these findings reflect the results of the previous study of intralesional steroid injections, in that onycholysis and subungual hyperkeratosis responded more favorably than did pitting. Because anthralin appeared to be more effective against these features, the investigators suggested that this agent may act primarily on the nail bed and hyponychium. Improvements in pitting seen in this study, however, may result from spontaneous regression, because topical application does not reach the nail matrix.  The primary side effect of topical use of anthralin, not prevented by application of triethanolamine cream, was pigmentation, which gradually resolved at the end of treatment.

Other therapeutic alternatives reported in the literature include orally administered colloidal silicic acid, 5% 5-fluorouracil cream, and 0.05% clobetasol proprionate topical solution.  Because these treatments have been used in only a small number of patients, no definite recommendations can be made regarding their safety and therapeutic value.

Despite the numerous available therapies for psoriatic nail disease, no single approach is clearly superior to the others. The current range of therapeutic approaches reflects the multifactorial origins of psoriatic nail disease and calls attention to the need for further investigation and clinical trials with larger patient population

Who was in goal for the Canuck’s victory and how many shutouts has he had this season?  Felix The Cat Potvin.  At press time The Cat has one shutout