Giardia lamblia — Ursache von Urtikaria und Pruritus oder zufällige Assoziation?

[Giardia duodenalis and its involvement in skin diseases]

BACKGOUND

Over the last thirty years, the scientific community has become increasingly interested in the intestinal flora, whether commensal or pathogenic, and its impact on other organs. In dermatology, the correlation between intestinal microbial agents and cutaneous lesions is well established. Giardia duodenalis, an intestinal parasite, has been particularly widely studied. The aim of this work is to provide a review of studies demonstrating the involvement of G. duodenalis in various forms of dermatosis.

PATIENTS AND METHODS

The data were obtained by an English-language literature search of Medline, PubMed and Google Scholar for the period 1975-2015. Among the thirty case reports since 1976, we selected the twenty most objective and clinically relevant.

RESULTS AND DISCUSSION

This review demonstrates that intestinal giardiasis may be an etiological factor, either alone or in combination with other agents, of various dermatoses through inflammatory and allergic mechanisms or intestinal hyperpermeability. The mucocutaneous lesions are varied: urticaria, angioedema, atopic dermatitis, erythema nodosum, Wells syndrome, among others. The role and origin of the infection are often unknown, and it is thus difficult to determine the interval between parasite infestation and the onset of skin lesions. Consequently, a fecal examination to identify G. duodenalis should be considered in chronic urticaria or angioedema, and where atopic dermatitis occurs in adulthood without any specific etiology. Therapeutic test should be done in every suspicion.

Particularities of allergy in the Tropics

Allergic diseases are distributed worldwide and their risk factors and triggers vary according to geographical and socioeconomic conditions. Allergies are frequent in the Tropics but aspects of their prevalence, natural history, risk factors, sensitizers and triggers are not well defined and some are expected to be different from those in temperate zone countries. The aim of this review is to investigate if allergic diseases in the Tropics have particularities that deserve special attention for research and clinical practice. Such information will help to form a better understanding of the pathogenesis, diagnosis and management of allergic diseases in the Tropics. As expected, we found particularities in the Tropics that merit further study because they strongly affect the natural history of common allergic diseases; most of them related to climate conditions that favor permanent exposure to mite allergens, helminth infections and stinging insects. In addition, we detected several unmet needs in important areas which should be investigated and solved by collaborative efforts led by the emergent research groups on allergy from tropical countries.

Mysterious chronic urticaria caused by Blastocystis spp.?

Species of the genus Blastocystis, which are single-cell, intestinal protozoan parasites of humans and animals, remain mysterious, with unclear clinical and epidemiologic significance. In recent years, many researchers have suggested a possible connection between Blastocystis spp. infection and chronic urticaria. In the present article, we review the literature and discuss the possible associations between the clinical symptomatology and pathogenicity of this organism in terms of its subtypes, morphologic forms, genetic diversity, and interactions with other intestinal microbiota.

Chronic urticaria in adults: state-of-the-art in the new millennium

Chronic urticaria has been explored in several investigative aspects in the new millennium, either as to its pathogenesis, its stand as an autoimmune or auto-reactive disease, the correlation with HLA-linked genetic factors, especially with class II or its interrelation with the coagulation and fibrinolysis systems. New second-generation antihistamines, which act as good symptomatic drugs, emerged and were commercialized over the last decade. Old and new drugs that may interfere with the pathophysiology of the disease, such as cyclosporine and omalizumab have been developed and used as treatments. The purpose of this article is to describe the current state of knowledge on aspects of chronic urticaria such as, pathophysiology, diagnosis and the current therapeutic approach proposed in the literature.

[Drug therapy of infectious diarrhea. Part 2: Chronic diarrhea]

Diarrheal diseases are among the most common diseases worldwide. In this review the current treatment recommendations for acute (Part 1) and chronic (Part 2) infectious diarrhea are summarized and typical enteropathogens are discussed. The second part of the article describes chronic diarrhea, its related pathogens and treatment. In contrast to acute diarrhea which is mainly caused by viral and typical bacterial pathogens, chronic diarrhea has mainly non-infectious origins. Protozoal pathogens, such as Giardia lamblia and Entamoeba histolytica in particular are found and more rarely bacterial pathogens, such as Tropheryma whipplei. Opportunistic pathogens cause diarrhea in immunocompromised patients, such as in HIV patients. In these patients cytomegalovirus (CMV) colitis or infections with Cryptosporidium spp., Cyclospora cayetanensis, Isospora belli or microsporidia have to be considered. Besides targeted specific antimicrobial therapy, anti-retroviral drugs improving the underlying immunosuppression and thus the reconstitution of the adaptive immune response remain a cornerstone of the treatment in HIV-positive patients.

Parasites induced skin allergy: a strategic manipulation of the host immunity

The absence of a consistent link between parasitoses and skin allergic symptoms in the clinical investigations contrasts to the fact that some parasites are the most potent inducers of immunoglobulin E that exist in nature. To shed some light into this question, this review is focused on the actual knowledge regarding parasites life cycle, interactions with host immunity, the influence on host behavior, and finally the role of all these factors on the skin allergy. The collected data demonstrate that parasites could manipulate the host behavior for its own benefit in different ways, altering its (epi)genetic, biochemical, immunologic or physiologic functions as well as altering its behavior and activity. In this context, skin allergy may be associated with certain stages of the parasites' life cycle and migration into biological barriers, but not necessarily with presence of the parasitosis in the host organism. As compared to T helper (Th) 1 response, the Th2 one, the eosinophilic infiltration and the complement inhibition could assure better conditions for the development of some parasites. Taken together, the suggested hypotheses could be a plausible explanation for the epidemiological puzzle regarding urticaria occurrence, Th2 response and parasitoses, but further studies are necessary to provide better-based conclusions.

KEYWORDS

Eosinophilic Infiltration; Host behavior; Parasites life cycle; Skin allergy; Th1/Th2 response.

Hospitalization of Cuban children for giardiasis: a retrospective study in a paediatric hospital in Havana

The medical records of the 185 children who, in 2007, were admitted to the Academic Paediatric Hospital 'Centro Habana', in the Cuban capital of Havana, because of giardiasis were analysed retrospectively. A standardized form was used to collect data on the socio-demographic characteristics, clinical features, laboratory diagnosis, treatment and length of stay of each child. Information on the 15 children who had incomplete medical records was excluded from the data analysis. Of the remaining 170 children, 85 (50·0%) were aged 1-4 years, 97 (57·1%) were male, and 106 (62·4%), 92 (54·1%) and 69 (40·6%) had presented with diarrhoea, vomiting, and/or abdominal pain, respectively. Most (91·2%) of the cases had been diagnosed by the microscopical examination of a duodenal aspirate, and the drugs that had been most used frequently were quinacrine and tinidazole, which had been given to 72 (42·4%) and 62 (36·5%) of the cases, respectively. The mean length of hospital stay was 4·9 days. Such information on the clinical characteristics of giardiasis among children living in an endemic area may be valuable to paediatricians and public-health officials who wish to screen for the disease.

[Parasites as a cause of urticaria. Helminths and protozoa as triggers of hives?]

Urticaria is one of the most prevalent disorders in dermatological practice. The disease can be incapacitating. There are clear pathophysiological and epidemiological hints that helminths and protozoa are rare but treatable causes of acute and chronic urticaria. Doctors and patients are often not aware that parasitic diseases are increasingly common even in industrialized countries due to a steep rise in migration and international travel. This review presents the most important parasitic causes of urticaria and provides relevant details regarding personal history, clinical presentation, diagnosis and therapy.