Hookworm Folliculitis: Report of Two Cases of Cutaneous Larva Migrans With Histologically Identified Follicular Involvement.

Abstract: Cutaneous larva migrans (CLM) is an ectoparasitic infestation predominantly caused by nematodes, specifically Ancylostoma braziliense and Ancylostoma caninum, found in tropical and subtropical regions. Although follicular involvement by the parasite is a rare manifestation, with approximately 20 cases reported in the English literature, its pathogenesis remains underexplored. The present study reports 2 cases of CLM presenting with follicular involvement in patients with pruritic lesions following travel to subtropical areas. The first of them is a 32-year-old woman who developed an abdominal skin lesion subsequent to a trip to Thailand and the second is a 28-year-old woman who exhibited a knee lesion after a volunteer mission in Senegal. Histologic examination revealed characteristic features of CLM, such as nematode larvae traversing the hair follicle. The hookworm larvae were observed creating tunnels within the external root sheath. In addition, they were interfacing with the vitreous layer, sparing the perifollicular connective tissue sheath and the Henle layer, and approaching the vicinity of the hair bulb. The application of skin ultrasound to guide the biopsy facilitated the visualization and identification of the parasite within the follicle in the latter case. This study not only underscores follicular involvement in CLM but also provides insights into its anatomopathological presentation and spread through the hair follicle.