In this isssue Passarini et al report on an outbreak of so called “chloracne” in Italy [1]. This article importantly reminds us of the many issues that relate to human dermatotoxicology in general, and dioxin exposure in particular. The skin is a key organ for the recognition of exposure to several poisons, and more specifically those related to the dioxin group. Such a “sentinel” role for the skin is most probably related to the fact that many poisons, be introduced either through the skin or systemically, are metabolised in the skin, and therein induce symptoms that may be specific for that poison. It was through the thoughfull clinical and histological analysis of the Italian group from the dermatology department of Bologna that a diagnosis of “chloracne” was made in several patients having been intoxicated in a holiday resort . For such a diagnosis, high clinical suspicion and specific laboratory markers are necessary, since important ecotoxicology issues may be involved. So how robust is the diagnosis of “chloracne” in this case series from Passarini et al. (1) and where are the guidelines for the minimum mandatory criteria for such a diagnosis?