Pseudo-delusory syndrome caused by Limothrips cerealium

Background: Limothrips cerealium (or "grain thrips") is an insect of the phylum Arthropoda, known as parasite of plants of the family Gramineae; human infestation is not frequently described in literature. Materials and methods: We report the case of a 59-year-old female farmer, come to observation because of intense itching and sensation of "walking insects" on her head, with no objective cutaneous signs except lesions due to scratching. After repeated visits, in which negative results of clinical and laboratory tests suggested the diagnosis of "delusory syndrome" (Ekboms syndrome), we finally isolated on her head some insects, identified by stereomicroscopy as L. cerealium. Careful inspection of the house of our patient allowed us to identify, as possible source of parasites, a wheat field and a deposit of grains used for animal feeding. Temporarily removing the patient from her usual environment resulted in complete clinical resolution. Results: Peculiarity of symptoms caused by this parasite and consequent problems for a correct diagnosis are discussed, as well as possible solutions. © 2006 The International Society of Dermatology.