Tungiasis is a parasitic skin disease caused by the adult female sand flea, Tunga penetrans. This tiny ectoparasite, also known as the chigoe flea or jigger, is native to tropical and subtropical regions across South America, the Caribbean, and sub-Saharan Africa. The female flea burrows into the outermost layer of the skin (the epidermis) and feeds on blood to produce eggs. As the flea enlarges, the surrounding skin develops a noticeable lesion.
Identifying Initial Symptoms
The earliest symptom of an embedded sand flea is a small, localized red or brown macule that evolves into a slightly raised bump (papule) within about 24 hours. The female flea rapidly grows in size to accommodate its developing eggs, causing the lesion to expand. A distinctive visual indicator is a small, dark or black pinpoint dot at the center of the lesion, representing the posterior end of the flea. This dark spot is the breathing and egg-expulsion orifice, usually surrounded by a whitish disc of swollen tissue.
Physical sensations include localized pain, a burning feeling, and intense itching. The pain increases significantly as the flea engorges and swells up to 10 millimeters, especially if pressure is applied. The affected area may become visibly red and inflamed due to the host’s inflammatory reaction. Over a period of four to six weeks, the flea lays its eggs, dies, and is sloughed off as the skin naturally sheds.
Where Sand Fleas Typically Embed
Since the female sand flea cannot jump very high, infestation occurs through direct contact with contaminated soil or sand, making the feet the most common site of penetration. Approximately 99% of all lesions occur on the feet, particularly around the nail beds. Specific sites include the soles, heels, areas between the toes, and under the toenails, where the flea finds soft tissue.
In populations like small children or individuals with limited mobility, infestations can occur in less typical locations. Since the parasite enters the skin at the point of contact with the ground, lesions may occasionally be found on the hands, elbows, or buttocks if the individual has been sitting or lying on infested soil. The flea rapidly burrows into the soft skin of the dermis layer, attaches to blood vessels to feed, and begins egg production.
Potential Health Complications
Leaving an embedded sand flea untreated raises the risk of severe secondary bacterial infections. The open wound acts as a gateway for pathogens like Staphylococcus aureus and Clostridium species, which can lead to complications such as cellulitis or abscess formation. Repeated scratching further facilitates the entry of bacteria, worsening inflammation and pain.
Chronic or severe infestations can lead to substantial physical disability, especially when multiple lesions are present on the feet. The pain and inflammation can make walking extremely difficult, leading to an altered gait and reluctance to bear weight. In severe cases, the resulting tissue damage can cause ulceration, deformation, loss of toenails, and tissue necrosis. The open sores are also a potential entry point for the bacteria that cause tetanus, a serious systemic infection, particularly in unvaccinated individuals.
Professional Diagnosis and Treatment
A medical professional typically diagnoses tungiasis through a visual inspection of the characteristic skin lesion. The presence of a whitish nodule with the distinctive dark central point is usually enough to confirm the infestation. Specialized tools like a dermatoscope may be used to confirm the presence of the parasite or its eggs within the lesion.
Once tungiasis is suspected, standard treatment involves the physical removal of the embedded flea under sterile conditions. A trained healthcare provider uses sterile instruments, such as a needle or scalpel blade, to carefully enlarge the entry point and extract the entire parasite. Self-removal is advised against, as incomplete extraction or crushing the engorged flea increases the risk of severe secondary infection.
After the flea is removed, the resulting wound must be thoroughly cleaned with an antiseptic solution. A topical antibiotic ointment is then applied to the site to prevent bacterial superinfection. The healthcare provider will also assess the patient’s tetanus vaccination status and administer a booster if necessary.