Nail Psoriasis: Treatment Options

ABSTRACT

Approximately 50% of patients^1,2 with psoriasis have nail psoriasis but the life time chance of nail changes must be much higher.³ Nail changes in psoriasis include pitting, thickening, onycholysis, discoloration, oily spots, splinter hemorrhages and paronychia.⁴ Treatment of choice depends on the form the psoriasis takes.⁵ Unfortunately, whatever the treatment used, failure and recurrence are common.⁶

Key Words:
psoriasis, corticosteroid, methotrexate, cyclosporine, photochemotherapy, topical cyclosporin

Treatment options⁵

• Moderate periungual psoriasis with nail ridging will respond to potent topical corticosteroid applied to the affected nail under polyethylene occlusion, used in combination with practical measures to protect the hands such as gloves and avoidance of mechanical or chemical trauma. Steroid needs to be continued for several months and ideally is only stopped when the cuticle is reformed. The need for hand and nail protection has to be emphasized to the patient.⁵
• Severe nail psoriasis Intralesional corticosteroid injection is still the longest lasting and most effective treatment when the nail dystrophy is of the appropriate form, the patient is well motivated and the clinician has the time and expertise to perform the procedure.
• Other treatments Keeping the nails short and avoiding manicure will minimize the isomorphic response in the nail unit, where trauma can provoke psoriasis.⁴ Nail psoriasis may improve during effective therapy of psoriasis at other sites, particularly when systemic agents such as methotrexate and cyclosporine are used. Whole body⁷ and local⁸ photochemotherapy, and topical cyclosporin⁹ are reported to be useful. In acrodermatitis continua, topical 5-fluorouracil¹⁰ has been used and systemic retinoids are often of benefit in all types of psoriasis affecting the nail.¹¹

Local application of corticosteroid for psoriatic onycholysis

The management of psoriatic onycholysis is often exacerbated by trauma, either from leverage at the nail tip caused by long nails or by attempts to clean beneath the nail with a sharp instrument. Steroid injections are usually not successful in such cases. It is often better to use local therapy after cutting the nail back to the point of attachment with the nail bed. This may be to the level of the lunula and requires a scalpel in a steady hand, but anesthetic is not usually needed. If the onycholysis is very extensive, it may be more satisfactory to call upon the services of a dermatologic surgeon. The exposed nail bed is very amenable to topical therapy with potent topical corticosteroid.⁵ On occasion it might be necessary to add an antimicrobial topical preparation (fusidic acid or mupirocin S. Maddin, Editor) if secondary invasion of the onycholytic space is suspected.⁶ The alternative treatment approach of advising the patient to apply corticosteroid solution between nail and nail bed has not proven to be successful.⁵

Intralesional injection of corticosteroid for severe nail psoriasis

The use of intralesional corticosteroids is the mainstay treatment for dystrophic changes in psoriatic nails.¹² William Gerstein of Montreal, while training with P. Samman in London, was the first to publish the results of steroid injected into the digit for nail psoriasis.¹³ Triamcinolone acetonide is the most readily available corticosteroid, the usual concentration is 2.5 mg/ml, or sometimes 5 mg/ml, injected into the proximal nail fold every three to four weeks for a total of four to six injections. It is practical to inject a volume of 0.1–0.2 ml into most sites. The injection can be given using a small syringe (such as an insulin syringe) with a 28–30 gauge needle firmly locked so that it won’t disengage.⁵ Subsequent injections have been given when necessitated by the frequency and extent of recurrences.¹²

A practical new approach to treatment by Drs. de Berker and Lawrence requires the injection of 10mg/ml into both the nail fold and the nail bed at three monthly intervals.¹⁴ For more specific details of this technique, see de Berker DAR, Lawrence CM. A simplified protocol of steroid injection for psoriatic nail dystrophy. Brit J Dermatol 1998; 138: 90–95.¹⁴ Pitting, ridging and nail thickening (hyperkeratosis) require proximal injection of steroid. Pitting in isolation may respond to superficial proximal nail fold injection but the latter two benefit from deeper matrix injections. Nail bed hyperkeratosis improves most if the nail bed is injected, and this always requires local anaesthetic.⁵

Use of anesthesia

Injected steroid does not always require local anesthetic. The injection site should be matched with the focus of the pathology.^5,15 Small injections given with a fine needle into the proximal nail fold of non-tender fingers can be tolerated by most patients. It is very important not to push deeper and end up in the matrix, as this will cause much more pain and require anaesthetic.⁵ A proximal ring block is best, as when combined with corticosteroid, distal blocks end up producing a turgid finger tip, temporary tamponade and patients who are more likely to have paresthesia or pain.⁵ If the anesthetic is given proximally, there is seldom any subsequent pain.

To gauge response, in most instances the proximal nail fold is a good place to start. This is always the case for pitting, and often true when ridging and nail plate thickening are associated with inflammation of the proximal nail fold. More generalized dystrophy warrants deeper injection into the matrix, and nail bed injection is helpful for subungual hyperkeratosis and some forms of nail thickening.⁵

Response to intralesional injection

Even after injecting both the nail bed and the nail fold, improvement rather than complete resolution is the norm. In de Berker and Lawrence’s study, subungual hyperkeratosis, ridging and thickening responded well, with benefit sustained for at least nine months; onycholysis and pitting, the most common signs, responded less well.¹⁴

Side effects of corticosteroid injection

Significant problems are rare. Injection into the matrix, as distinct from the proximal nail fold, often provokes a small subungual hemorrhage which is incorporated into the nail plate as it grows out. Although Port-o-jet and Dermojet jet guns have been used to deliver corticosteroid into the proximal nail fold, there are several reports of infection and nail plate damage associated with their use and there is the possibility of spreading infection between patient and doctor because of the blood and steroid that splashes back from the skin surface.⁵ Atrophy from steroid injection although uncommon, has been reported in patients being treated for nail psoriasis.^5,13 The risk of damage to the extensor tendon of the interphalangeal joint remains theoretical.⁵

Summary

In treating nail psoriasis, excluding onycholysis and pustular forms, the proper use of intralesional corticosteroid provides a 60–80% chance of improvement, if the injections have been directed to the appropriate part of the nail apparatus. This benefit will be sustained for up to nine months and sometimes longer.
Drs. de Berker and Lawrence ^5,14

Acknowledgment

I would like to thank Dr. David de Berker and Dr. Richard Scher for their suggestions and assistance.
Dr. S. Maddin, Editor

Nail Psoriasis: Response to intralesional injection of corticosteroid14

References

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5. de Berker DAR. Personal communication, April, 1997.
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8. Handfield-Jones SE, Boyle J, Harman RRM. Local PUVA treatment for nail psoriasis. Brit J Dermatol 1987; 116: 280
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10. Tsuli T Nishimura M. Topically administered fluorouracil in acrodermatitis continua of Hallopeau. Arch Dermatol 1991; 127:27–8
11. Baran R. Retinoids and the nails. J Dermatol Treat 1990; 1: 151–154
12. Basuk PJ, Scher RK, Ricci AR. Dermatologic diseases of the nail unit in Nails: Therapy, diagnosis, Surgery. Scher RK, Daniel CRD editors. WB Saunders, Philadelphia 1990.
13. Gerstein W. Psoriasis and lichen planus of the nails. Arch Dermatol 1962; 86: 419–421
14. de Berker DAR, Lawrence CM. A simplified protocol of steroid injection for psoriatic nail dystrophy. Brit J Dermatol 1998; 138: 90–95
15. Yu RCH, King CM. A. double blind study of superficial radiotherapy in psoriatic nail dystrophy. Acta Derm Venereol (Stockh) 1992; 72: 134–136
16. Scher RK. Personal communication, 1997.