BI27 Strongyloides stercoralis screening in dermatology

Abstract

Abstract Strongyloidiasis is a major neglected tropical disease and chronic parasitic infection caused by Strongyloides stercoralis. An estimated 30–100 million people are infected worldwide, with acquisition via contact with contaminated soil. Accurate data for the UK are unavailable, but there is a prevalence of > 20% in certain immigrant populations. Many cases are asymptomatic; without therapy, the infection may be lifelong. Testing is more common in dermatology since the advent of dupilumab as infection can be life-threatening in the immunocompromised. Symptoms reported with strongyloidiasis include not only pruritus and urticaria but also abdominal and respiratory issues. Standard diagnostic testing of strongyloidiasis relies on demonstration of the parasite in faeces, body fluids or tissue samples, although serology is most often used in dermatology. The aim of our study was to assess why dermatologists are ordering Strongyloides serology and whether the results could identify features of infection. All Strongyloides serology tests sent by dermatology from two centres from January 2021 to December 2022 were analysed. Data collected included demographics, reason for testing, symptoms, foreign travel, test results and treatment. In total, 187 tests were sent. Patient demographics are provided in Table 1. The reasons for testing were before starting dupilumab in 57.2% (n = 107), pruritus in 13.4% (n = 25) and urticaria in 3.2% (n = 6/187). There was a recorded history of other symptoms of strongyloidiasis in five patients, and a recorded history of foreign travel in four. Twelve per cent of results were positive (n = 23/187), 6.9% (n = 13) were borderline and 80.7% (n = 151) were negative. There was no major skew toward a reason for testing in those who were positive/borderline. Eight per cent (n = 3/36) of those with positive/borderline results had other recorded symptoms. Of the positive/borderline results, 31% (n = 11/36) were not treated (mostly because they did not go on to have immunosuppression), 28% (n = 10) were treated with a single dose of ivermectin, 31% (n = 11) with two doses and 8% (n = 3) with four doses. The main reason for Strongyloides testing in dermatology is before starting dupilumab. A low proportion of the patients with positive/borderline results had symptoms, although often this was not recorded. A higher proportion of individuals of Asian or African ancestry had positive/borderline results. We shall also discuss evidence behind the methods of and reasons for Strongyloides testing.Table 1Patient demographicsDemographicAll tests (n = 187)Positive/borderline tests (n = 36)Male115 (61.5)22 (61)Female72 (38.5)14 (39)White52 (27.8)5 (14)Asian95 (50.8)22 (61)Black21 (11.2)5 (14)Other/not stated19 (10.2)5 (14)Data are presented as n (%).