Dermatology Online Journal

Psoriatic Onycho-pachydermo-periostitis
Jonathan S. Dosik, M.D.
Dermatology Online Journal 7(1):11

Department of Dermatology, New York University

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PATIENT: J.C., 59-year-old man

DURATION: One year

DISTRIBUTION: Great toes, scalp, face, and penis

History

The patient denies a personal or family history of skin disease prior to March, 1999, when he developed progressive bilateral great toe nail onychodystrophy, which was associated with painful swelling of the distal great toes. In December, 1999, the patient developed scaly, erythematous plaques on the scalp, face, and penis. He denies involvement of other digits or joints. He has no medical or drug history. A trial of sulfasalazine recently has been started. If this treatment fails, a trial of methotrexate is planned.

Physical Examination

Erythematous plaques with scale were noted on the scalp, forehead, and glans penis. The great toenails were thick and exhibited onycholysis, subungual debris, and periungual erosions. Diffuse, tender, swelling of the distal great toes was present. The remaining digits, nails, and joints were unaffected.

Figure 1	Figure 2

Laboratory Data

The erythrocyte sedimentation rate was 31 mm/hr. A complete blood count, electrolytes, liver function tests, C-reactive protein, and urinalysis were normal. Potassium hydroxide preparations of the toenails were negative for fungal hyphae. Radiographs of the feet showed periosteal thickening of the bilateral distal phalanges.

Histopathology

A scalp biopsy showed regular psoriasiform epidermal hyperplasia with confluent parakeratosis with collections of neutrophils, a thin granular layer, and pallor of the upper layers of the epidermis. Thin, suprapapillary plates and dilated blood vessels in the papillary dermis were demonstrated. A periodic acid-Schiff stain is negative for fungi.

Diagnosis

Psoriatic onycho-pachydermo-periostitis

Comment

Psoriatic onycho-pachydermo-periostitis is a recently described entity that includes psoriatic onychodystrophy, soft-tissue thickening above the terminal phalanx, and radiologic involvement of the phalanx with an exuberant periosteal reaction and bone erosions.[1,2] Lesions are typically painful and result in discomfort. The most common form of onychodystrophy in psoriatic onycho-pachydermo-periostitis is onycholysis associated with longitudinal ridges of the nail plate. It may involve the nails of any fingers or toes; however, the nails of the great toes are involved in most reported cases.[3]

Psoriatic onycho-pachydermo-periostitis has been proposed to be a unique variant of psoriatic arthritis.[3] It frequently occurs without peripheral arthritis or spondyloarthropathy, but it may be found in association with other forms of psoriatic arthritis, such as distal interphalangeal joint arthritis. It shares, along with other forms of psoriatic arthritis, an increased frequency of HLA-B27. The pathology of psoriatic onycho-pachydermo-periostitis is not understood; however, a proposed mechanism is analogous to that of the ossifying enthesopathy of seronegative arthritis, in which the inflammation is transmitted from the involved articular cartilage to the insertions of ligaments and tendons. As such, psoriatic onycho-pachydermo-periostitis could be explained by the anatomic relationship between nail and the terminal phalanx, whereby inflammation could spread from the subungual dermis to the terminal phalanx through the fibrous septa which directly join them and are deeply inserted into the bone.

The treatment of psoriatic onycho-pachydermo-periostitis is disappointing.[4] Non-steroidal inflammatory drugs and retinoids have been shown to be ineffective. Methotrexate provided moderate benefit in one reported case. As cyclosporine has been found to be useful in other forms of psoriatic arthritis, it may prove to be a useful alternative treatment in disabling forms of psoriatic onycho-pachydermo-periostitis.

References

1. Goupille P, Laulan J, Vedere V, Kaplan G, Valat JP. Psoriatic onycho-periostitis. Report of three cases. Scand J Rheumatol 1995;24(1):53-4. PubMed

2. Boisseau-Garsaud AM, Beylot-Barry M, Doutre MS, Beylot C, Baran R. Psoriatic onycho-pachydermo-periostitis. A variant of psoriatic distal interphalangeal arthritis? Arch Dermatol 1996;132(2):176-80. PubMed

3. Goupille P, Vedere V, Roulot B, Brunais J, Valat JP. Incidence of osteoperiostitis of the great toe in psoriatic arthritis. J Rheumatol 1996;23(9):1553-6. PubMed

4. Ruzicka T. Psoriatic arthritis. New types, new treatments [editorial] Arch Dermatol 1996;132(2):215-9. PubMed

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