When a self-limited skin infection is anything but

A 72-year-old woman from a remote Amerindian community in the Amazon lowland of Colombia is brought to medical attention because of progressive immobility and severe pain involving both feet. Over the past several months, she has become increasingly unable to stand or walk and now spends most of the day resting in a hammock.

She lives in a small hut without a solid floor and has limited access to food and medical care. Several dogs live in close contact with her household. Because of chronic knee pain, she rarely leaves the dwelling and frequently places her feet directly on the dirt floor. Family members report that similar lesions have occurred intermittently for years but have worsened markedly over time.

Physical examination reveals hundreds of embedded nodular lesions involving the soles, lateral aspects of the feet, and interdigital spaces. Many lesions are closely packed and layered on top of one another, with surrounding hyperkeratosis and areas of necrosis. Similar clusters of lesions are noted at the ankles and knees. A strong malodor is present. The patient appears cachectic and dehydrated.

Laboratory evaluation shows severe anemia and mild leukocytosis. Examination of several lesions demonstrates viable ectoparasites embedded in the superficial layers of the skin.

Tungiasis is a neglected tropical disease caused by penetration of female sand fleas (Tunga penetrans, and less commonly T. trimamillata) into the superficial layers of the skin. Once embedded, the flea hypertrophies, enlarging dramatically over several days and inducing intense local inflammation, pain, and itching.

Although tungiasis is inherently self-limited—each flea eventually dies after releasing eggs—individuals living in endemic, resource-poor settings are repeatedly reinfected. Over time, parasite load accumulates, and disease severity correlates directly with the number of embedded fleas.

Very severe tungiasis occurs almost exclusively in individuals with pre-existing conditions that limit mobility, such as advanced age, disability, chronic joint disease, or neuropsychiatric disorders. Prolonged contact with dirt floors, intradomiciliary transmission, poverty, malnutrition, and lack of access to health care form a web of causation that allows a normally benign infection to become life-threatening.

Complications include secondary bacterial infection, tetanus, severe anemia due to chronic blood loss, cachexia, and complete immobility. Effective treatment requires topical antiparasitic therapy (such as dimeticone formulations), supportive care, and addressing environmental sources of reinfection.

• Tungiasis is usually self-limited, but repeated reinfection can lead to devastating disease in endemic settings.

• Disease severity correlates directly with parasite burden.

• Elderly, disabled, or immobile individuals are at highest risk for very severe tungiasis.

• Poverty, intradomiciliary transmission, and limited health care access are critical determinants of morbidity and mortality.

• Dimeticone-based topical therapy is effective even in very severe disease.

Miller H, Ocampo J, Ayala A, Trujillo J, Feldmeier H. Very severe tungiasis in Amerindians in the Amazon lowland of Colombia: A case series. PLoS Negl Trop Dis. 2019;13(2):e0007068.