Pterygium inversum unguis. Report of 19 cases and review of the literature

Pincer Nail Deformity Associated with Systemic Lupus Erythematosus

“…5,6 In one study, 11 of 56 patients (19.6%) with lupus erythematosus had red lunulae, with 7 of the 11 suffering from SLE. 5 Caputo et al 7 showed that ptery- gium inversum unguis is usually acquired and most often causally related to systemic connective tissue diseases, particularly progressive systemic sclerosis and SLE. Patients with SLE may show an altered nail keratinization process leading to leukonychia, nail pitting, and/or ridging, plus onycholysis or onychomadesis.…”

Pterygium inversum unguis associated with stroke

“…After this first description, a total of 34 cases of PIU, either congenital or acquired, have been reported in the English-language literature. [2][3][4][5][6][7][8][9] These 34 cases are summarized in Table I. The majority of the cases of PIU are seen in women between the ages of 20 and 70 years.…”

“…Seventeen of 34 acquired cases of PIU (50%) have been described primarily in patients with connective tissue diseases. 4,9 The fingernails are affected more commonly than the toes. There has been only one patient described with congenital PIU with bilateral toenail involvement.…”

Diagnosis Using the Nail Bed and Hyponychium

“…7,8 As the nail plate grows the hyponychium extends forward and the distal nail groove is eliminated (Fig. 2).…”

“…7 This finding occurs commonly in females. 8 Pterygium inversus Diagnosis Using the Nail Bed and Hyponychium unguis is often acquired; however, some cases may be associated with familial or congenital causes. 9 Acquired forms may occur because of a systemic connective tissue disease or may be idiopathic.…”