Tungiasis is an ectoparasitic condition caused by the cutaneous penetration of a Tunga penetrans flea. These tiny fleas are commonly found in sandy beaches and areas with warm, dry soil. Risk factors for infection include household dirt floors, lack of closed footwear, and the presence of farm animals. In some poverty-stricken regions, the prevalence of tungiasis approaches 50%. Tungiasis is also common in returned travelers, usually following beach vacations.
The female flea burrows into the skin of a host, feeds on blood, matures, lays eggs, and eventually dies in the cutaneous tissue. The rear of the flea remains visible as a black spot and serves for respiration and excretion of feces. A pronounced inflammatory response is seen leading to characteristic lesions. The vast majority of lesions are seen on the feet with the area at the rim of the toenails being the preferred site.
Early-stage lesions demonstrate erythema surrounding a 0.5- to 2.0-mm black dot. A yellowish-white halo then develops around the dot with increasing erythema, pain, and pruritus. Later stage lesions develop a brownish coloration with crusting and desquamation. Secondary bacterial infection is common. Tungiasis is usually a clinical diagnosis; a small central dot representing the flea is an important clue. A biopsy will show the flea, but is not required for diagnosis.
Management and Disposition
No oral drug has been proven to be effective against an embedded flea. Occlusive ointments will kill the flea, but does not aid in removal. The flea can be removed with excision or gently with a needle. Untreated, the flea will eventually die after 4 to 6 weeks with subsequent sloughing of the flea and eventual resolution of the inflammatory lesion. Antibiotics are indicated for secondary infection.
Tungiasis is known by numerous local names including sand fleas, jiggers, bicho de pie, nigua, pigue, suthi, and chigoe.
The causative flea is native to the West Indies and was first reported in a crewman who sailed with Christopher Columbus. They are now widely found throughout Latin America, Africa, and Asia.
The initial stage of penetration is manifested by a stinging sensation followed by itching that is surprisingly described as being pleasant.
Numerous cases of tetanus and gangrene have been reported in patients with secondarily infected T penetrans lesions.
Tungiasis. Acute tungiasis lesion from an adult flea seen on the foot of a 30-year-old American aid worker in the Democratic Republic of Congo. Lesions are more obvious in patients who do not habitually walk barefoot. (Photo contributor: Seth W. Wright, MD.)
Tungiasis. Chronic lesions in a Kenyan man. Crusted scales are common in those with chronic infections and thicker skin. (Photo contributor: Lawrence B. Stack, MD.)