A rare case of tungiasis: Clinical presentation and successful management

Dear Editor,

Tungiasis, a parasitic skin infestation caused by the sand flea Tunga penetrans, is a neglected tropical disease predominantly seen in resource-poor regions of sub-Saharan Africa, the Caribbean, and Latin America. Due to increased international travel, cases are occasionally encountered in non-endemic regions. The infection is characterized by the penetration of a fertilized female flea into the epidermis, where it hypertrophies while feeding on host blood, leading to the development of a distinctive nodular lesion with a central dark punctum. The sand flea is also known as the “chigoe,” “jigger,” and “pique” in different countries.^[1,2]

A 44-year-old male farmer presented with multiple painful, pruritic, popular, and nodular lesions over both feet, each displaying a central dark spot. The patient had recently returned from a rural area where he walked barefoot. Multiple lesions on the plantar aspect of the feet were hyperpigmented and tender, showing a whitish halo surrounding a black punctum [Figure 1]. No systemic symptoms or signs of dissemination were observed. Dermoscopy revealed a central pigmented area encircled by a pale halo and radial linear vessels, correlating with the inflammatory reaction surrounding the embedded mass [Figure 2].

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Figure 1:

Multiple hyperpigmented pruritic papules and nodules over bilateral feet.

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Figure 2:

Dermoscopy revealed a central darkly pigmented area encircled by a pale halo, and the surrounding erythema showed the embedded flea. (Dermalite DL4 dermatoscope, non-polarised white light, 10x).

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On histopathological examination with hematoxylin and eosin staining under 40x magnification, an embedded parasite was seen in the stratum corneum, with a thick eosinophilic cuticle, residual tracheal rings, eggs in varying stages of development, inflammatory infiltrates composed of lymphocytes and eosinophils, and mild dermal fibrosis features diagnostic of T. penetrans infestation [Figure 3].

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Figure 3:

Histopathology revealed a thick eosinophilic cuticle (green arrow), tracheal rings (red star), eggs in different stages (blue arrow), suggestive of tungiasis. (Hematoxylin and eosin, 40x.)

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Gentle surgical curettage was performed to remove the embedded fleas, after which the lesions were cleaned and dressed. The patient was treated with a single dose of oral ivermectin (200 μg/kg), topical permethrin 5% overnight on the first day, followed by urea-based keratolytic cream and one coat of topical petroleum jelly to achieve occlusion. Systemic antibiotics were given prophylactically to avert secondary bacterial infection. Tetanus prophylaxis was also administered. The lesions showed improvement in a month with scarring and granuloma formation. The patient was continued with keratolytic cream and followed up to check for reinfestation [Figure 4].

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Figure 4:

Follow-up image after a month, showing clinical improvement with scarring.

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T. penetrans (sand flea or jigger flea) is a minute hematophagous insect belonging to the order Siphonaptera and family Tungidae, and is the smallest flea known to infest humans. The adult flea measures approximately 1 mm in length, is wingless, laterally compressed, and reddish-brown in color, with piercing-sucking mouthparts and powerful hind legs adapted for jumping. Unlike other fleas, only the fertilized female penetrates human skin, usually at the periungual or plantar sites of the feet. After penetration, the flea undergoes neosomy, a unique entomological phenomenon characterized by progressive abdominal hypertrophy.

During neosomy, the embedded female flea enlarges dramatically to a size of 5–10 mm, with its anterior portion embedded within the epidermis and dermis, while the posterior abdominal tip remains in contact with the external environment. This exposed posterior end appears clinically as a characteristic central black punctum, which represents the posterior spiracles and genital opening and serves for respiration, defecation, copulation, and expulsion of eggs. Microscopically, the distended abdomen is packed with numerous oval eggs and shows a thick chitinous exoskeleton, visible tracheal rings, and a blood-filled gut – features that are diagnostic of T. penetrans infestation.

Eggs are intermittently expelled through the posterior opening and fall into the surrounding soil, where they develop into larvae and pupae before emerging as adult fleas. After completing oviposition over a period of several weeks, the flea dies in situ, and residual chitinous structures may persist within the skin, eliciting a chronic inflammatory or foreign-body granulomatous response. Recognition of these distinctive entomological features – particularly neosomy, posterior abdominal exposure, and egg-filled hypertrophied abdomen – is central to the diagnosis of tungiasis and helps distinguish it from other parasitic and inflammatory dermatoses.^[3,4]

Differentials to be considered such as parasitic and arthropod-related conditions include furuncular myiasis, which presents as a boil-like lesion with a central pore and serous discharge; tick bites or retained tick mouthparts, often associated with a localized inflammatory reaction; scabies nodules, which are intensely pruritic and usually multiple; and insect bite reactions, which are typically grouped and lack a persistent central punctum. Infectious and inflammatory conditions of the feet may also resemble tungiasis. These include bacterial furunculosis or abscess, acute or chronic paronychia, infected corns or callosities, and plantar warts, which are hyperkeratotic and disrupt normal skin lines. Foreign body granuloma should be considered when there is a history of trauma or barefoot walking, while pyogenic granuloma may mimic an inflamed lesion but is characterized by rapid growth and a tendency to bleed. Neoplastic and vascular lesions, though less common, are important exclusions, particularly in chronic or atypical cases. Epidermoid cysts, subungual hematoma, glomus tumor, and acral lentiginous melanoma may present as nodular or pigmented lesions on the feet and periungual areas. Careful clinical examination, dermoscopy demonstrating the characteristic black nodules with a surrounding whitish halo, and correlation with exposure history are essential to accurately differentiate tungiasis from these conditions.^[5,6]

Tungiasis is primarily treated by complete sterile extraction of the embedded flea, which remains the gold standard, followed by local antiseptic care. Topical low-viscosity dimeticone is a highly effective, painless, and safe alternative, especially for multiple lesions or in endemic settings, as it kills the flea by physical suffocation. Topical antiparasitic agents may be used as adjuncts, while oral ivermectin has limited efficacy and is not recommended as monotherapy. Antibiotics are indicated only for secondary bacterial infection, and tetanus immunization status must always be assessed. Supportive care and preventive measures, such as footwear and environmental hygiene, are essential to reduce recurrence.^[6,7]

Tungiasis is often under-recognized outside endemic zones, yet prompt diagnosis is crucial to prevent complications. The characteristic clinical hallmark – a papular-nodular lesion with a central black punctum – should raise high clinical suspicion, especially in travelers or rural workers with a history of barefoot exposure. Differential diagnoses include plantar warts, pitted keratolysis, deep mycosis, myiasis, and foreign-body granulomas. Failure to recognize tungiasis early may result in superimposed cellulitis, abscess formation, gangrene, or even tetanus.