Acta Dermato-Venereologica 99-2CompleteContent | Page 13

164 CLINICAL REPORT Ultrasound Assessment of Psoriatic Onychopathy: A Cross-sectional Study Comparing Psoriatic Onychopathy with Onychomycosis Mireia MORENO 1 , Maria Pilar LISBONA 2† , Fernando GALLARDO 3 , Gustavo DEZA 3 , Marta FERRAN 3 , Caridad PONTES 4 , Jesús LUELMO 5 , Joan MAYMÓ 2 and Jordi GRATACÓS 1 Department of Rheumatology, 4 Clinical Pharmacology and 5 Department of Dermatology, Hospital Universitari Parc Taulí, Sabadell, Department of Rheumatology, Parc de Salut Mar, 3 Department of Dermatology, Parc de Salut Mar, Universitat Autònoma de Barcelona/ Universitat Pompeu Fabra, Barcelona, Spain † Dr Lisbona died just before completion of the study. 1 2 This cross-sectional study evaluated the usefulness of an ultrasound technique in assessment of nail chan- ges in 35 patients with psoriatic onychopathy and 25 with nail dystrophy secondary to onychomycosis. All patients underwent 3 examinations: a complete clini- cal assessment; a nail ultrasound study; and fungal culture. Nails of patients with psoriatic onychopathy presented a thinner nail plate and nail bed, measured by ultrasound, than did those with onychomycosis. The percentage of patients with a power Doppler signal ≥2 at nail bed was significantly higher in psoriatic ony- chopathy than in onychomycosis, and structural bone lesions were more frequent in psoriatic onychopathy than in onychomycosis. These results suggest that the presence of structural damage and high-power Dopp- ler signal are the main ultrasound findings supporting a diagnosis of psoriatic onychopathy. Key words: ultrasound; nail; psoriatic onychopathy; onycho- mycosis. Accepted Oct 3, 2018; E-published Oct 3, 2018 Acta Derm Venereol 2019; 99: 164–169. Corr: Fernando Gallardo, Department of Dermatology, Parc de Salut Mar, Universitat Autònoma de Barcelona/Universitat Pompeu Fabra, ES-08003 Barcelona, Spain. E-mail: [email protected] P soriatic arthritis (PsA) is a heterogeneous chronic inflammatory disease with a wide clinical spectrum and variable course. Early diagnosis and treatment of PsA could contribute to the prevention of clinical and radio- logical progression and functional deterioration (1, 2). Nail involvement is common in patients with psoriasis. Nails are affected in 15–50% of patients with psoriasis, with the lifetime incidence of nail involvement being approximately 80% (3). Although psoriatic onychopathy (PsO) is diagnosed solely on the basis of clinical signs, it is considered a major clinical marker for the presence or development of PsA. Moreover, PsO is often the only psoriatic finding at the time of PsA diagnosis in cases with no other cutaneous lesions of psoriasis. Eight features of PsO have been identified for the Nail Psoriasis Severity Index (NAPSI) score: 4 involve the nail matrix (pitting, leukonychia, red spots in the lunula, and nail plate crumbling) and 4 the nail bed (onycholysis, splinter haemorrhages, subungueal hyperkeratosis, and doi: 10.2340/00015555-3060 Acta Derm Venereol 2019; 99: 164–169 SIGNIFICANCE Ultrasound is an emerging, non-invasive, inexpensive, ima- ging technique with proven evidence for use in the assess- ment of different skin disorders. The aim of this study was to differentiate nail psoriasis from onychomycosis using an ultrasound technique, since clinical differentiation of these conditions is challenging, especially if psoriasis pre- sents with nail disease alone. The long-term therapy and prognosis for these disorders are different, therefore early and adequate diagnosis is essential. Presence of structural bone damage and a high-power Doppler signal were the main observed ultrasonographic findings supporting a di- agnosis of nail psoriasis and suggesting an association with psoriatic arthritis. oil spot/salmon patch). The NAPSI (4) is an objective and reproducible tool for estimating the severity of PsO, intended as a good measurement of the efficacy of thera- peutic interventions. Ultrasound (US) has proven a useful, non-invasive and inexpensive imaging technique for screening superficial tissues, such as the nails (5–7). Substantial evidence for the role of US in the assessment of onychopathy in PsA has been published (8, 9). However, to our knowledge, no previous studies have analysed the capacity of this imaging technique to help clinicians differentiate PsO from other nail changes. Onychomycosis (OM) affects 3–4% of the population, with prevalence increasing with age (10, 11). Clinical differentiation between PsO and OM is challenging, especially when nail disease alone is present. PsO and OM have different clinical and prognostic implications and require different long-term therapy with potential side-effects, it is essential to ensure both an early and adequate diagnosis (12). The aims of this study are to evaluate the usefulness of US in the assessment of PsO, and to differentiate PsO US findings from those found in OM. METHODS Design and patients This was a cross-sectional study in which consecutive psoriatic patients with nail involvement (with or without PsA according to Classification Criteria for Psoriatic Arthritis (CASPAR) clas- This is an open access article under the CC BY-NC license. www.medicaljournals.se/acta Journal Compilation © 2019 Acta Dermato-Venereologica.