Itchy skin rashes are a frequent reason to seek medical advice. The symptoms may be caused by hypersensitivity reactions to arthropod bites, waterborne parasites or setae from moth caterpillars and are sometimes mistaken for spontaneous urticaria or eczema. Some of these pests are resurging in Switzerland and elsewhere and increasingly responsible for emergency consultation. In this article we review itchy skin rashes caused by bed bugs, scabies, lice, cercariae, Pyemotes spp, caterpillars and harvest mites, which may be confounded with urticaria and allergic contact dermatitis. We detail here clinical manifestations, topographical distribution of skin lesions, epidemiology, treatment and preventive measures.