A 65-year old man presented with skin lesions on his chest and left arm and shoulder six weeks after i returning from a cacation in Belize at the beach in the fain forest. The lesions occasionally stung, drained a dark exudates, and enlarged despite two weeks of treatment with cephalexin. The patient had no constitutional symptoms. Physical examination reverled five nodules of varying sizes with surrounding erythema and a central pore through which a single, moving larva was observed. This condition is caused by -
The symptoms of this disease include: Severe pruritus Pain Inflammation and swelling Lesions and ulcerations, with black dots in the center Left untreated, secondary infections, such as bacteremia, tetanus, and gangrene, can occur. In all cases, tungiasis by itself only caused morbidity, though secondary infection may lead to moality. The life cycle section presents the Foaleza stages from the flea's developmental perspective. The discussion is specific to symptoms of human infection. The clinical presentation in humans follows the Foaleza Classification as the stage of infection will determine the symptoms present. The following discussion will give an overview of the symptoms beginning in stage 2 because patients are not likely to present themselves at the early stages of infection, mostly because the flea's burrowing is usually not felt. This may be due to a keratolytic enzyme secreted during stage 1. The patient with a single flea may present as early as stage 2 when, though the erythema is barely perceptible, a boring pain and the curious sensation of pleasant itching occur. This inflammatory reaction is the initial immunological response to the infestation. Heavily infested patients may not notice a stage 2 infection due to the other fleas' causing irritation as well. Feces may be seen, but this is more common in the 3rd stage.Around the third day after penetration, erythema and skin tenderness are felt, accompanied by pruritus (severe itching) and a black furuncular nodule surrounded by a white halo of stretched skin caused by the expansion of the flea. Fecal coils may protrude from the center of the nodule where the flea's anus is facing upward. They should be washed off quickly as the feces may remain in the skin unless removed. During this 3a substage, pain can be severe, especially at night or, if the nodule is on the foot, while walking. Eggs will also begin to be released and a watery secretion can be observed. The radical metamorphosis during the 3rd to 6th day after penetration, or neosomy, precedes the formation of a small caldera-like rim rampa as a result of the increased thickness of the flea's chitin exoskeleton. During the caldera formation, the nodule shrinks a bit and it looks as if it is beginning to dry out; this takes 2 weeks and comprises substage 3b. At the third week after penetration and substage 4a, the eggs' release will have stopped and the lesion will become smaller and more wrinkled. As the flea is near death, fecal and water secretion will stop altogether. Pain, tenderness, and skin inflammation will still be present. Around the 25th day after penetration, the lesion looks like a black crust and the flea's carcass is removed by host repair mechanisms and the skin begins to heal. With the flea gone, inflammation may still persist for a while. Although patients would not present within the 5th stage of tungiasis as the flea would be dead and no longer in the body, this stage is characterized by the reorganization of the skin (1-4 weeks) and a circular residue of 5-10 mm in diameter around the site in penetration. An intraepithelial abscess, which developed due to the presence of the flea, will drain and later heal. Although these disease residues would persist for a few months, tungiasis is no longer present. In severe cases, ulcers are common, as well as complete tissue and nail deformation. A patient may be unable to walk due to severe pain if too many of the lesions are present in the feet. Suppuration (pus formation), auto-amputation of digits ( ainhum), and chronic lymphedema may also be seen. If the patient is not vaccinated, tetanus is often a complication due to secondary infection. Gangrene is another common complication of severe infestation and superinfection. Staphylococcus aureus and Wolbachia endobacteria can be transmitted by the chigoe flea, as well as nearly 150 other different pathogens. For these reasons, the chigoe flea should be removed as soon as possible Ref Harrison20th edition pg 1078
Tungiasis
Cutaneous leishmaniasis
Bot fly
d) Onchocerciasis
Infection