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Superficial skin myiasis: causes, symptoms, diagnosis, treatment
Last reviewed: 06.07.2025
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Superficial myiasis of the skin (myasis cutis syperficialis) is most often caused by the larvae of blue blowflies (family Calliphora erythocephalei Meig), spring blowflies (family Calliphora vomitoria L., Profophermia terraenovae RD), green blowflies (family Lucilia caesar), gray blowflies (family Coprosarcophaga naemorrhoidalis Fall), cheese flies (family Piophila casei) and even houseflies (Musca domastica), house flies (Muscina stabulaus), etc.
The aforementioned flies, attracted by the putrid smells of decaying tissue, lay eggs in ulcers, festering wounds, abrasions, punctures, scratches and other damage to the skin and mucous membranes, including the nose, eyes, and folds in the area of the external genitalia. The larvae that hatch from the eggs, usually in extremely large numbers, often seed the entire lesion. There are especially many of them under the overhanging edges of the ulcers. Objectively, grayish-white islands consisting of seemingly swarming semolina grains are visible in the lesion.
Parasitism of larvae in a wound usually does not cause any particular concern to patients. Only some of them indicate the possibility of a feeling of moderate itching or "crawling ants". Diseases of superficial myiasis of the skin are relatively benign. This is due to the fact that the larvae, not being able to digest living, i.e. normal tissue, are limited to devouring pus and decomposed necrotic tissue. Then, at the end of their development cycle, these larvae fall off the skin, and their pupation occurs outside the human body.
Along with the described benign superficial myiasis, in some cases its more severe course is possible. This is observed most often in widespread purulent processes in the area of the conjunctiva of the eyes, mucous membrane of the nose, ears. There are known cases of crawling housefly larvae into the urethra and the development of myiasis of the urogenital organs - myasis urogenitalis. In this case, the crawling of larvae into the urethra can occur both when eggs get on dirty bed linen, from where the hatched larvae can then penetrate into the urethra, and after the direct transition of larvae from the folds of the external genitalia to the urethra.
In addition to urogenital myiasis, under appropriate conditions, in particular, when a person swallows the larvae of some of the above-mentioned flies and, for example, has low acidity of gastric juice, intestinal myiasis may develop - myasis intestinalis. In these cases, patients note the following symptoms: pain in the intestinal area, accompanied by tenesmus, as well as frequent loose stools. The disease usually proceeds acutely, although in some cases, especially with repeated infections, a longer, protracted course may be observed. In this case, patients can excrete live larvae with liquid feces. The release of larvae to the outside can also occur with vomit.
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