Approach Considerations
A number of surgical treatment methods are available. The flea can be removed from its cavity with sterile instruments, but this is more difficult when the flea is engorged. The orifice needs to be enlarged, and the entire nodule should be curetted or excised. Following surgical extraction of the flea, thoroughly cleanse and cover the remaining crater with a topical antibiotic cream to prevent secondary infection. [2]
A course of oral antibiotics may be instituted if secondary infection is suspected. Ensure that tetanus prophylaxis is up to date.
Removed parasite shown with needle. Courtesy of Wikimedia Commons [https://commons.wikimedia.org/wiki/File:Puce_chique_(Tonga_penetrans).jpg].
Consultations and follow-up
Consultations are only rarely indicated and are generally for complications of a secondary infection. Follow-up care confirms a complete resolution of all pain and physical findings. Application of an antibiotic ointment several times a day to the wounds after flea extraction is recommended. [1]
Topical Treatments
Dimethicone
A 2-component dimethicone, available under the brand name NYDA®, has been shown to cause 80-95% of all embedded sand fleas to lose viability within 7 days. It is most effective when applied topically directly to the affected area. Further, dimethicone is considered wholly nontoxic and very safe for extended human use. [58, 59] In a clinical trial of 106 individuals with tungiasis, treatment with NYDA® caused no observable adverse effects. [60] Dimethicone’s physical mode of action (entering the flea’s respiratory tract and preventing oxygen from entering the brain) limits the chances of the sand flea developing drug resistance. [61] The additional properties of NYDA®, such as the 2 different viscosities, provide a solution for tungiasis cases in which mechanical extraction is difficult. [62] After treatment, natural skin repair will eliminate the dead parasites. If any viable fleas remain, they will be unable to expel eggs. [60]
Zanzarin
The insect repellant Zanzarin, a lotion consisting of coconut oil, jojoba oil, and aloe vera, was shown to reduce the number of newly embedded fleas and skin lesions, as well as to almost completely reverse the cutaneous pathology, when applied twice daily. [63] In a study in Madagascar, a twice-daily application of Zanzarin was found to be much more effective than the use of closed toed shoes. It is believed that this is because shoes are less financially accessible and often not culturally desired. [63] Zanzarin has now been removed from the market but is made of ingredients that could be accessed locally and so manufactured in areas affected by tungiasis.
Topical antibiotics and petroleum jelly
Topical ivermectin, metrifonate, and thiabendazole have been reported as effective. Occlusive petrolatum suffocates the organism. Twenty-percent salicylated petroleum jelly (Vaseline) applied 12-24 hours in profound infestations caused the death of the fleas and facilitated their manual removal. [6] However, these treatments do not remove the flea from the skin, and they do not result in quick relief from painful lesions. [64, 65]
Neem and coconut oil
Some Kenyan communities use the oil combination as a traditional treatment. A 2019 study of a cold-pressed 20% virgin neem seed oil and 80% virgin coconut oil treatment with a targeted application was not more effective than the endorsed KMnO4 foot bath but did offer improvements in other areas. The combination led to significant clinical improvement in acute pathology and an increased number of embedded fleas with abnormal development. The neem seed’s antibacterial and anti-inflammatory properties, as well as its azadirachtin content, is the primary reason for these improvements. More effective results may be seen if the neem seed oil and azadirachtin concentration are increased. [61]
Other known treatments
Reported topical treatments for tungiasis include cryotherapy and electrodesiccation of the nodules. Application of formaldehyde, chloroform, or dichlorodiphenyltrichloroethane (DDT) to the infested skin has been used, but such treatments are not recommended and may cause patient morbidity.
Deterrence and Prevention
Prevention of tungiasis centers around using closed shoes in endemic areas. Keeping classroom floors clean and free of organic matter may also be helpful in preventing transmission in crowded endemic areas among vulnerable populations.
However, these 2 strategies are often more theoretical than practical given the circumstances of transmission in settings of deep poverty. Shoes are rarely worn in areas of potential transmission, indoors or even in classrooms, and shoes may quickly wear out or develop holes, making the wearer vulnerable again.
Studies comparing the use of shoes to twice daily application of the plant-based insect repellant Zanzarin for the prevention of tungiasis show more protective effect with the latter. [8, 66] In areas with a high endemicity of sand fleas, daily application of Zanzarin was found to be very efficacious at preventing tungiasis. [67, 63]
Other control measures include treating infested areas with pesticides and treating infected reservoir hosts. Spraying malathion on the ground in some infested villages was found to significantly reduce the incidence of tungiasis, as was the use of methoprene, an insect growth regulator. A topical aerosol containing chlorfenvinphos 4.8%, dichlorphos 0.75%, and gentian violet 0.145% was found to be highly effective against pig tungiasis. Since pigs are an important reservoir for the fleas, treatment of the domestic pig population could have a large positive effect on tungiasis prevalence. [68]
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A. Tangential cut through a fully developed, gravid flea embedded in the stratum corneum of the epidermis. The flea's head and thorax are enfolded in the hypertrophic anterior abdominal segments. The epidermis is hyperplastic and shows papillomatosis, parakeratosis, and hyperkeratosis.B. Tangential cut through the posterior abdominal segments of an embedded sand flea. Next to the chitinous cuticle, a microabscess has formed.C. Dead parasite; the exoskeleton of the posterior abdominal segment has remained intact; the cuticle has disintegrated at the epidermal–dermal interface. The carcass is infiltrated by neutrophils, and pus has formed.D. The head of the flea is located at the epidermal–dermal interface, has penetrated the basal membrane, and is surrounded by many erythrocytes, presumably having leaked from a blood vessel. The abdomen of the parasite is separated from host tissue by a thick, chitinous cuticle.
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A tungiasis lesion in substage 3a.
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Scanning electron micrograph of flea on day 3 after penetration. The hypertrophic zone between abdominal segments 2 and 3 is gaining a bulging shape and looks like a life-belt (x100).
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Scanning electron micrograph of flea on day 8 after penetration. The hypertrophy zone has taken the shape of a sphere. The 3 parts of abdominal segment 2 are completely bent apart. Together with the newly developed, crescent-shaped chitinous clasps, the anterior part of the flea looks like a 3-leafed clover (x32).
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Scanning electron micrograph of flea 6 hours after beginning of penetration. The penetration is almost completed; only the last abdominal segments protrude through the skin (x240).
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Scanning electron micrograph of flea in stage 2. The rear end, the genital opening, and the 4 pairs of stigmata form a miniature cone, which towers above the crater caused by pushing in abdominal segments 7 and 8 (x190).
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Life cycle of Tunga penetrans - Fortaleza stages included. Compiled and designed by Fausto Bustos and Lucas Manfield.
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Histopathologic findings in tungiasis.
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Life cycle of the chigoe flea, Tunga penetrans. Courtesy of the CDC.
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Complicated Tungiasis infection. Courtesy of Dermatology Atlas (http://www.atlasdermatologico.com.br/index.jsf) and Samuel Freire da Silva, MD.
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Tungiasis lesion under toenail. Courtesy of Dermatology Atlas (http://www.atlasdermatologico.com.br/index.jsf) and Samuel Freire da Silva, MD.
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Example of complicated infection with multiple tungiasis lesions and possible secondary infection. Courtesy of Wikimedia Commons [author R Schuster, https://commons.wikimedia.org/wiki/File:Jigger_infested_foot_(2).jpg].
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Illustration of Tunga penetrans (sand flea) in its enlarged state. Courtesy of Wikimedia Commons [https://commons.wikimedia.org/wiki/File:ChiggerBMNH.jpg].
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Removed parasite shown with needle. Courtesy of Wikimedia Commons [https://commons.wikimedia.org/wiki/File:Puce_chique_(Tonga_penetrans).jpg].
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Tunga penetrans flea. Courtesy of Wikimedia Commons [author Philipp Weigell, https://commons.wikimedia.org/wiki/File:Tunga_penetrans_%281%29.JPG].
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Image of Tungiasis infection on both feet. Courtesy of PLOS [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 Neglected Tropical Diseases. 2019 Feb 7. Online at: https://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0007068.].
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Graphical abstract of predicted tungiasis occurrence within sub-Saharan Africa. Courtesy of MDPI [Deka MA. Mapping the Geographic Distribution of Tungiasis in Sub-Saharan Africa. Tropical Medicine and Infectious Disease. 2020 Jul 24;5(3):122. Online at: https://www.mdpi.com/2414-6366/5/3/122#.].
Tables
Medication Name |
Dosage/Application |
Contraindications |
Availability |
Notes |
|---|---|---|---|---|
Apply directly to the affected area once or twice daily.
If legion numbers are under 40 or legions are in clusters: Apply 3 drops of NYDA® (approximately 50 μL each) to the exposed posterior side of the flea. Repeat the procedure 3x over 10 minutes.
If fleas are in excessive hyper-keratotic skin and located on top of each other: NDYA® must be used to wet the skin intensely and repeatedly. |
No known contraindications. Shown to be safe for extended use. |
Available under the brand name NYDA®. But not available in all tungiasis endemic areas. |
||
0.8% ivermectin, 0.2% metrifonate and 5% thiabendazole lotions, applied 2 consecutive days. |
No contraindications reported. |
All are readily available except for metrifonate, which is no longer commercially available. |
||
Apply to all infected areas and areas at risk for tungiasis infection twice daily. |
No known contraindications. |
No longer commercially available, but made of ingredients that could be locally manufactured in areas where tungiasis is common. |
||
One drop (approximately 0.05 ml) of a mixture of 20% cold-pressed virgin neem seed oil and 80% virgin coconut oil applied to the embedded flea’s abdominal tip on days 1 and 3. |
Actives in cold-pressed neem oil are not toxic following oral, inhalation, or dermal exposure. |
May be locally available where both neem trees and coconut palms grow. |
The mixture requires proper storage as azadirachtin has a high sensitivity to ultraviolet light, pH, and temperature. |
