Treatment of Urticaria caused by severe cryptosporidiosis in a 17 ... - BMC Infectious Diseases

Cryptosporidium is a zoonosis and intestinal pathogen that infects humans and various animals. The parasite is transmitted through water, food, and feces-contaminated materials, and settles in the epithelial cells of the intestinal region where it reproduces asexually and increases in number. The presence of parasites in the intestine cause's mild to severe gastrointestinal symptoms. The parasite causes severe watery diarrhea that can lead to death in immunocompromised patients and children if left untreated [13]. A recent study showed, zoonosis transmission of Cryptosporidium species due to contact with cows and calves is prevalent among farm workers and their household members in Isfahan city [14]. According to the results of this study, most of the people infected with parasites were without diarrhea or clinical symptoms. It is worth discussing this as it probably represents a further risk factor for transmission especially if this was shown to be in young children from which transmission is likely to occur [14]. In our case, the father of the family was in close contact with cows and calves, and perhaps this factor caused the parasite to be transmitted to the child.

Several conditions have been found to be related to urticaria symptoms, whereas the term chronic idiopathic urticaria identifies the high percent of conditions in which a pathogenetic factor has not been found [15]. Identifying the cause of urticaria requires ruling out many other conditions. A special form of urticaria is autoimmune urticaria, in which antibodies are produced against IgE receptors or IgE itself [16]. Food allergens, drugs, colors, perfumes, insect bites, chemicals and physical sensitivities are other causes of urticaria. The existence of some diseases related to the immune system, viral and bacterial infections are also other causes of urticaria. Although intestinal parasites have been cited as a possible cause of urticaria, only a limited number of documented cases have shown a relationship between parasitic infection and urticaria [17]. A large number of infections caused by parasitic worms such as Fasciola hepatica, Strongyloides stercoralis, Echinococcus granulosus, filaria, Ascaris lumbricoides, Trichinella spiralis, and Schistosoma sp. have been associated with allergic skin symptoms, and antiparasitic drugs have not been effective in treating urticaria caused by them [12, 17, 18].

The mechanism of urticaria caused by Cryptosporidium, like other enteric pathogens, is not fully understood. The authors hypothesized a pathogenesis similar to that underlying the IgE-mediated allergic response: Cryptosporidium antigens induce specific Th2 clones on lymphocytes, which in turn produce specific cytokines (ILs 3, 4, 5 and 13) and lead to the switch of antibodies and IgE production. This mechanism can be confirmed by performing a skin biopsy and observing the increase in mast cells and mononuclear cells. This reaction will be responsible for increasing the production of histamine and other mediators of early and late inflammatory reaction.

The increase of circulating eosinophils in most patients with parasitic infection is another factor related to allergic sensitivity [19].

A number of antibiotics have been used to treat intestinal cryptosporidiosis. However, most of them cannot kill the organism completely [20]. Paromomycin is an aminoglycoside that cannot be completely absorbed when taken orally, and as an anti-cryptosporidial drug, it has a high rate of recurrence after treatment [21]. Perhaps one of the reasons is that paromomycin is placed inside the intestinal tract and has little activity on the intracellular forms of the parasite. Nitazoxanide (Alinia) is a new drug with broad activity against protozoa and intestinal worms. This drug inhibits ferredoxin reductase, which is the main enzyme in the parasite's anaerobic metabolism [22]. Nitazoxanide has recently been approved by the FDA for the treatment of Giardia and Cryptosporidium in immunocompetent children aged 1 to 12 years. Along with drug treatment, appropriate intravenous nutrition, supportive hydration is necessary due to severe diarrhea. In our case, complete improvement of urticaria was observed using nitazoxanide, a drug that has no anti-allergic and anti-inflammatory effects, without taking any antihistamine. Unfortunately, we do not know the exact mechanism of urticaria caused by Cryptosporidium. Anyway, various reasons have been discussed for the cause of urticaria caused by parasitic infections, such as the role of specific IgE, Th2 cytokine skewing, eosinophil's and coagulation system and finally circulating immune complexes and complement system [15,16,17,18].

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