Dermatofibromas and arthropod bites: is there any evidence to link the two?

30 patients with dermatofibromas were questioned closely about contacts with stinging or blood-sucking arthropods before the development of their lesions. Their responses were not significantly different from those of a matched control group. 100 dermatofibromas were examined by dissection, histology, and after acid digestion of the collagenous material; no traces of arthropod skeletal tissues were found. These data are not consistent with the theory that the mechanical presence of arthropod tissues is necessarily, or even usually, a cause of dermatofibromas.