[Giardia duodenalis and its involvement in skin diseases]

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.

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.

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.