A Case Report of Pterygium Inversum Unguis Associated with Systemic Lupus Erythe

Xiao-Li Zhang, Yan Teng, Hao Chen, Mei Ju, Yi Liu, Mu-Sang Liu∗

1Clinical Trials and Cosmetics Testing Center, Hospital for Skin Diseases (Institute of Dermatology), Chinese Academy of Medical Sciences and Peking Union Medical Colleges, Nanjing, Jiangsu 210042, China; 2Department of Dermatology, Zhejiang Provincial People’s Hospital, People’s Hospital of Hangzhou Medical College, Hangzhou, Zhejiang 310014, China; 3Department of Pathology, Hospital for Skin Diseases (Institute of Dermatology), Chinese Academy of Medical Sciences and Peking Union Medical Colleges, Nanjing, Jiangsu 210042, China; 4Department of Physiotherapy, Hospital for Skin Diseases (Institute of Dermatology),Chinese Academy of Medical Sciences and Peking Union Medical Colleges, Nanjing, Jiangsu 210042, China; 5Department of Mycology, Hospital for Skin Diseases (Institute of Dermatology), Chinese Academy of Medical Sciences and Peking Union Medical Colleges, Nanjing, Jiangsu 210042, China.

Abstract

Keywords: pterygium inversum unguis, systemic lupus erythematosus, case report

Introduction

Pterygium inversum unguis (PIU), also known as ventral pterygium,is a rare abnormality characterized by adherence of the distal nail bed to the ventral surface of the nail plate,resulting in obliteration of the distal groove. PIU was first described by Caputo and Prandi in 1973 in a woman who developed ventral pterygium on multiple fingers of both hands without definite cause.1This condition,which have been reported in few cases,can be congenital,idiopathic,or secondary to systemic connective tissue diseases or other.We herein report a case of acquired PIU associated with systemic lupus erythematosus(SLE),which is rare ofitskind in the Chinese dermatologic literature.

Case report

A 33-year-old woman presented with a 2-year history of multiple telangiectasias in the abdomen of the fingers in May 2018. The telangiectasias were scattered between bright red or purple patches. She was initially treated for frostbite with topical heparin ointment.One month before the current visit, she presented with proximal muscular weakness, a malar rash, photosensitivity, knee and ankle arthritis,and PIU of the fingers.She complained for mild to moderate pain while clipping her fingernails.She was then admitted to our hospital.

Figure 1. Fingers (excluding the thumbs)showing the adherence of the distal nail bed to the ventral surface of the nail plate, resulting in obliteration of the distal groove.

Physical examination of the fingernails (excluding the thumbs) revealed marked subungual keratotic thickening between the distal hyponychium and ventral nail plate.The distal portion of the nail bed was adherent to the ventral surface of the nail plate,obliterating the nail groove(Fig.1).The patient had no family history of a similar nail abnormality.The laboratory findings were consistent with the diagnosis of SLE (positive for ANA, Ro/SSA, La/SSB,U1-SnRNP antibody, anti-dsDNA, and Smith antibody).

The patient was treated with methylprednisolone (40 mg/day), mycophenolate mofetil (1.0g twice a day), and hydroxychloroquine (0.2g twice a day). In addition, her nails were treated by topical application of tretinoin 0.025%. Approximately 2 months after the beginning of treatment,most of the SLE symptoms had disappeared or improved; however, the nail disorder has not been improved. The patient had no adverse or unanticipated reactions and was satisfied with the effect.

Regular follow-up has been undergoing until the time of this writing.The patient continued to use topical agent of tretinoin 0.025% at the sites of pterygium intermittently and attend the clinic regularly. The SLE symptoms were well controlled,while PIU was not significantly aggravated or alleviated. Without obvious discomfort, the patient refused other possible treatment options and gave the informed consent for publishing her case.

Discussion

We have herein described a case of a 33-year-old woman with a recent diagnosis of SLE,in whom the distal portion of the nail bed of the bilateral fingers(excluding the thumbs)was adherent to the ventral surface of the nail plate,obliterating the groove.The patient in the present case had an acquired form of PIU affecting all of the fingernails(excluding the thumbs)without involvement of the toenails.

Acquired PIU is reportedly associated with connective tissuediseasessuchassystemicsclerosis2orotherconditions such as stroke,onychophagia,allergic dermatitis,or use of gel polish, and after allogeneic haematopoietic stem cell transplantation.3–6Becauseoftherarityofthiscondition,its exactorigin remains speculative.In order tobetterrecognize the origin and pathology of this infrequent disease, Zaias et al.7classified it into three categories:congenital aberrant hyponychium, acquired irreversible PIU, acquired reversible extended hyponychium.Acquired form of the disorder may be linked to abnormal distal circulation or exposure to certain chemical stimuli, which leads to destruction of the matrix,reactive hyperkeratosis and thus pterygium formation.4,7This may explain the pathogenesis of our patient,who could be categorized into acquired irreversible PIU,secondary to SLE.

The management of PIU is not well defined. Different treatments, including topical retinoids, hydroxypropyl chitosana,and electrodissection,can reportedly produce a good response.8-9The most effective strategy involves treatment of the underlying cause of acquired PIU.In our case,however,the PIU did not improve after 2 months of treatment of SLE and use of topical retinoids.The patient was still undergoing follow-up at the time of this writing.

In conclusion, patients with PIU must be evaluated to rule out associated causes,and these patients require longterm follow-up examinations to detect the development of connective tissue diseases such as SLE.