DESCRIPTION

Infestation of the epidermis by the infectious larvae of certain nematodes, classically manifesting with an intensely pruritic, serpiginous skin lesion

EPIDEMIOLOGY

Worldwide distribution but most frequent in warmer climates, including the Caribbean, Africa, South America, Southeast Asia, and southeastern United States

RISK-FACTORS

• Contracted from soil contaminated with dog and cat feces
• Occupational exposures occur from crawling under buildings, such as among plumbers and pipefitters.

PATHOPHYSIOLOGY

• Route of spread
  • Primary host (dog or cat) passes eggs to ground through feces.
  • Warm, sandy soil acts as an incubator.
  • Eggs mature into rhabditiform larvae (noninfectious), which molt in 5 days to filariform larvae (infectious).
• Humans are accidental hosts.
• Filariform larvae penetrate the epidermis either through hair follicles, skin fissures, or through intact skin with the use of proteases.
• Larvae are unable to penetrate the basement membrane of the dermis; therefore, the infection remains limited to the epidermis.
• Larvae cannot complete their life cycle in the human host and die within weeks to months.
• Symptoms are due to hypersensitivity to the organism or its excreta.

ETIOLOGY

• Most common organism is the dog or cat hookworm, Ancylostoma braziliense.
• Other species include Ancylostoma caninum, Uncinaria stenocephala, and Bunostomum phlebotomum.