Psoriatic Onycho-pachydermo-periostitis

Psoriatic Onycho-pachydermo-periostitis Chih-Chieh Chan Tsen-Fang Tsai Psoriasis is a chronic inflammatory scaling skin disorder affecting approximately 0.1~3.0% population. Nail and joint involvement are not uncommon in psoriatic patients. However, psoriatic onychopathy with an underlying bony/periosteal involvement in the distal phalanx is exceptionally rare. In our case, psoriasis with psoriatic nails and enlarged distal digits without evidence of joint involvement led to the diagnosis of psoriatic onycho-pachydermo-periostitis, which is recognized as a special entity in the spectrum of psoriatic arthritis. We reported this rare case and reviewed related literature.(dermatol Sinica 23: 86-90, 2005) Key words: POPP, Psoriatic onycho-pachydermo-periostitis, Psoriatic arthritis, Psoriasis 0.1~3.0% ( 23: 86-90, 2005) INTRODUCTION Psoriatic onycho-pachydermo-periostitis (POPP) is a newly described entity in the expanding spectrum of psoriatic arthritis. 1 It is characterized by enlarged (clubbed) digits without evidence of adjacent joint involvement or arthritis in patients with psoriasis. We herein report the first case of POPP in Taiwan and review the literature. CASE REPORT The patient was a 34-year-old man who noticed slowly enlarging digits since his early twenties. He was quite well in the health history before this event. The involved digits increased in size only at distal phalanges, which were neither tender nor pruritic (Fig. 1). There was no difficulty in movements and the only discomfort was the cosmetic issue. He received serial stud- From the Department of Dermatology, National Taiwan University Hospital Accepted for publication: December 20, 2004 Reprint requests: Tsen-Fang Tsai, M.D., Department of Dermatology, National Taiwan University Hospital, No. 7 Chung-Shan South Road, Taipe 100, Taiwan TEL: 886-2-23562141 ext. 5734 FAX: 886-2-23934177 86 Dermatol Sinica, June 2005

Fig. 1 Clubbed fingers of all digits. Fig. 2 Clubbed fingers with subungual hyperkeratosis and onycholysis and nail pitting. ies for his clubbed fingers in a medical center at the age of 30 years old under the impression of acromegaly or clubbed fingers. The electrocardiogram, chest radiography and pulmonary function test were without abnormal findings. A complete blood count, biochemistry panel and the endocrine study including growth hormone were within reference levels. On examination, the clubbed fingers were obvious. He had mild acne and a pus-like lesion in the nail bed of the left ring finger, which was noticed for 2 weeks before this visit. Several finger nails showed typical findings of psoriatic nails, i.e. nail pitting, subungual hyperkeratosis, oily spots, splinter hemorrhage and onycholysis (Fig. 2). There were also several erythematous scaly papules on the trunk and glans penis. His scalp was erythematous with productive dandruff. The X-ray films of hands and feet revealed cap-shaped spur-like formation at fingertips and toetips with drumstick appearance (Fig. 3). The distal interphalangeal joint spaces were without abnormal findings. A further magnetic resonance image (MRI) study showed circumferential thickening of the periosteum and soft tissue surrounding the distal phalanges (Fig. 4). Cortical erosions with periosteal reaction were significant, sparing the adjacent joint spaces, which brought the radiological diagnosis of periostitis. The patient's father and uncle had psoriasis and arthritis. His brother was also disturbed by clubbed fingers. The patient was diagnosed as having psoriasis with psoriatic nail and clubbed Fig. 3 Cap-shaped spur-like formation at fingertips with drumstick appearance (arrows). Fig. 4 Periosteal circumferential thickening of the distal phalanges with cortical erosion (high signal areas indicated by arrows). The adjacent joint spaces are intact. (A: Enhanced T1- weighted MR image with fat suppression; B: T2-weighted MR image with fat suppression) Dermatol Sinica, June 2005 87

finger. There were no evidences of active arthritis. The final diagnosis was psoriatic onychopachydermo-periostitis, which was considered a special subtype of psoriatic arthritis. DISCUSSION Nail involvement is relatively common in psoriatic patients. According to a previous study in Taiwan, nearly half patients had psoriatic onychopathy. 2 However, nail disease as the initial presentation, also noticed in our case, was only found in 3.5% patients. Psoriatic nails with clubbed fingers were even rarer in the literature. Clubbing is the formation of bulbous swelling of the soft tissue of the terminal phalanx of a digit with subsequent loss of the normal angle between the nail and nail bed. The causes of digital clubbing can be divided into primary (idiopathic) or secondary forms (Table I). 3 The causes of primary digital clubbing include primary hypertrophic osteoarthropathy and familial clubbing. The secondary causes of digital clubbing include cardiopulmonary diseases (such as cyanotic congenital heart disease, primary pulmonary fibrosis, lung cancer, etc.), gastrointestinal diseases (such as Crohn s disease, liver cirrhosis), endocrinopathy (such as acromegaly, thyroid acropachy) and pregnancy. Most secondary causes of digital clubbing can be easily diagnosed from detailed history taking, physical examinations and laboratory studies. Though clubbing is a common physical finding in many underlying pathological processes, the mechanisms remain unknown to date. 3 Psoriatic onycho-pachydermo-periostitis, first described as ivory phalanx, 4 was very rare worldwide. The disease was characterized by psoriatic involvement leading to onychopathy, soft tissue thickening and bone erosions with periosteal reaction close to the terminal phalanx, and special radiological findings of the distal phalanges. 5 Though previously proposed to be a variant of psoriatic arthritis, 6 the joint spaces, however, were mostly free from involvement at the time of diagnosis and most patients presented no joint limitation or signs of arthritis. Treatments successful for psoriatic arthritis brought disappointing results in treating POPP, which suggests possible divergent pathogeneses in these two conditions. Boisseau- Garsaud et al. 5 suggested possible pathophysiologic mechanisms that inflammation is transmitted from the psoriatic nail, passing through the adjacent subungual dermis to the underlying bone by the same mechanism as in enthesopathies. In 1972, Moll and Wright 7 first introduced 5 subgroups of psoriatic arthritis: (1) predominantly distal interphalangeal (DIP) involvement, (2) arthritis mutilans, (3) symmetric polyarthritis resembling rheumatoid arthritis, (4) asymmetric oligoarthritis, and (5) sacroiliitis or spondylitis. So far, Moll and Wright s classification is the most commonly accepted (Table II). However, the changes of POPP do not fit readily to Moll and Wright s classification since it is a different entity from isolated DIP joint involvement. Helliwell et al. 8 modified Moll- Wright classification of psoriatic arthritis. POPP fits their description into the subtype 3: extraarticular osseous manifestation. The line between POPP and psoriatic arthritis is obscure and some author regarded POPP as the antecedent step toward psoriatic arthritis. 10 POPP could precede, parallel, or follow the definite diagnosis of psoriasis. Clubbed fingers/toes might be the first presentation of upcoming psoriasis. In our case, the drumstick digits antedated the cutaneous presentation and diagnosis of psoriasis for 10 years. Therefore, those who present gradually enlarging digits should raise the clinical impression of POPP if he or she is seronegative without reasonable findings in cardiovascular assessments or any other possible causes that can explain the clubbing. In previous reported cases, all patients with clubbed fingers were evaluated for their digits radiologically by simple X-ray studies, which revealed only bony components rather than nearby soft tissue reactions. Some of them who showed significant findings of clubbed fingers clinically, however, were not quite compatible with the little X-ray findings. 11-13 Our case is the first POPP patient to have been evaluated 88 Dermatol Sinica, June 2005

Table I. Classification of digital clubbing 3 Digital clubbing (hypertrophic osteoarthropathy/hoa) Primary HOA Idiopathic Pachydermoperiostosis (PDP)* Others Familial Secondary HOA Cardiac Congenital cyanotic heart disease Infective endocarditis Pulmonary Cystic fibrosis Pulmonary fibrosis Cancer: primary or metastatic Chronic infections Mesothelioma AV fistulae Hepatic Liver cirrhosis Hepatocellular carcinoma Intestinal Inflammatory bowel diseases Pregnancy related Miscellaneous Grave s disease Thalassemia Diverse malignancies POEMS syndrome POPP* Others *PDP and POPP can be differentiated by the causes: primary vs. secondary HOA radiologically with a MRI study, and showed notable and distinct soft tissue component reactions on the MRI film. The image methods used for diagnosing peripheral enthesitis, which is similar to the mostly accepted concept of the pathogenesis of POPP, include conventional radiography, bone scintigraphy, ultrasound and MRI. 14 In X-ray studies, the typical lesions are mostly detected in advanced cases since the bony erosion and soft tissue calcification are not found in early acute inflammatory phase. Ultrasound is readily applicable but still is depending largely upon individual examiners. Besides, the fingertips are not proper locations for ultrasound probes to approach. MRI, instead, is the most sensitive method for identification of active enthesopathies since perientheseal inflammation is easily recognized in 14, 15 fat-suppressed T2-weighted MRI sequences (Fig. 4B). Bone scintigraphy is most useful in the diagnosis of patients with multilobular inflammation in multiple enthesis, which is next to ultrasound or MRI studies when these exams fail to yield a definite result. These evidences may suggest that MRI rather than an X-ray study is better in evaluating this kind of periosteal reactions. The MRI provides a new window for precise demonstration of the anatomic pathology of entheseal inflammation and periostitis in POPP patients. Our case was treated with systemic retinoid (acitretin) for his nail involvement. It was discontinued shortly after because of side effects. Nail bed lesions and clubbed fingers remained prominent after several months of top- Table II. Classification of psoriatic arthritis Moll and Wright 7 1.predominantly distal interphalangeal (DIP) involvement 2.arthritis mutilans 3.symmetric polyarthritis resembling rheumatoid arthritis 4.asymmetric oligoarthritis 5.sacroiliitis or spondylitis Helliwell et al. 8 1.peripheral arthritis similar to rheumtoid arthritis (RA) but in which DIP joint involvement is common and associated with other features, such as dactylitis and enthesopathies 2.sacroiliitis and spondylitis 3.extra-articular osseous manifestations Koo T et al. 9 1. polyarticular 2. RA-like 3. oligoarticular 4. erythrodermal 5. distal form 6. pustular Dermatol Sinica, June 2005 89

ical phototherapy. Treating POPP is difficult to date. Non-steroid anti-inflammatory drugs, corticosteroids, retinoids, cyclosporine and sulfasalazine 16 had been tried but there s no proved benefit. Methotrexate was the only drug reported to be effective in treating two symptomatic patients. 13, 17 Recently, adalimumab, a monoclonal antibody of tumor necrosis factor, was also reported to bo effective. 18 Further clarification of the accurate pathogenesis of POPP is necessary before reaching effective managements. REFERENCES 1. Fournie B, Viraben R, Durroux R, et al. : [Psoriatic onycho-pachydermo-periostitis of the big toe. Anatomo-clinical study and physiopathogenic approach apropos of 4 cases]. [French] Rev Rhum Mal Osteoartic 56: 579-582, 1989. 2. Chen HH, Tseng MP, Tsai TF: An epidemiologic study of Taiwanese psoriatic patients in a single clinic. Dermatol Sinica 21: 216-224, 2003. 3. Martinez-Lavin M, Pineda C: Hypertrophic osteoarthropathy. In: Hochberg MC, Silman AJ, Smolen JS, et al., eds. Rheumatology. 3rd ed. London: Mosby, 1763-1767, 2003. 4. Resnick D, Broderick TW: Bony proliferation of terminal toe phalanges in psoriasis: the "ivory" phalanx. J Can Assoc Radiol 28: 187-189, 1977. 5. Boisseau-Garsaud AM, Beylot-Barry M, Doutre MS, et al.: Psoriatic onycho-pachydermo-periostitis. A variant of psoriatic distal interphalangeal arthritis? Arch Dermatol 132: 176-180, 1996. 6. Goupille P, Vedere V, Roulot B, et al.: Incidence of osteoperiostitis of the great toe in psoriatic arthritis. J Rheumatol 23: 1553-1536, 1996. 7. Moll J, Wright V: Psoriatic arthritis. Semin Arthritis Rheum 3: 55-78, 1972. 8. Helliwell P, Marchesoni A, Peters M, et al.: A reevaluation of the osteoarticular manifestations of psoriasis. Br J Rheumatol 30: 339-345, 1991. 9. Koo T, Nagy Z, Sesztak M, et al.: Subsets in psoriatic arthritis formed by cluster analysis. Clin Rheumatol 20: 36-43, 2001. 10.Marguery MC, Baran R, Pages M, et al.: [Psoriatic acropachydermy]. [French] Ann Dermatol Venereol 118: 373-376, 1991. 11. Jury CS, Fleming C, Kemmett D: Severe nail dystrophy associated with painful fingertips. Diagnosis: psoriatic onychopachydermoperiostitis (POPP). Arch Dermatol 136: 925-930, 2000. 12.Fietta P, Manganelli P: Pachydermoperiostosis and psoriatic onychopathy: an unusual association. J Eur Acad Dermatol Venereol 17: 73-76, 2003. 13.Bauza A, Redondo P, Aquerreta D: Psoriatic onycho-pachydermo periostitis: treatment with methotrexate. Br J Dermatol 143: 901-902, 2000. 14.Koehler L, Kuipers JG, Zeidler HK: Enthesopathy. In: Hochberg MC, Silman AJ, Smolen JS, et al., eds. Rheumatology. 3rd ed. London: Mosby, 1275-1281, 2003. 15.Olivieri I, Barozzi L, Padula Ai. Enthesiopathy: clinical manifestations, imaging and treatment. Baillieres Clin Rheumatol 12: 665-681, 1998. 16.Anders HJ, Sanden S, Kruger K: [Psoriatic onycho-pachydermo- periostitis]. [German] Z Rheumatol 61: 601-604, 2002. 17.Kroiss MM, Vogt T, Finkenzeller T, et al. : [Psoriatic onycho-pachydermo- periostitis]. [German] Z Rheumatol 61: 598-600, 2002. 18.Bongartz T, Harle P, Friedrich S, et al.: Successful treatment of psoriatic onychopachydermoperiostosis with adalimumab. Arthritis Rheum 52: 280-282, 2005. 90 Dermatol Sinica, June 2005