'Wake sign': an important clue for the diagnosis of scabies.

Japan is currently experiencing many outbreaks of scabies, occurring mainly in long-term care facilities. Scabies burrows, the only pathognomonic lesion for scabies, often occur on the creases of the palms, and are followed by a pattern of scale reminiscent of the 'wake' left on the surface of water by a moving bird or a ship (wake sign).(1-4) The wake sign is useful because (i) it is specific for scabies, (ii) it is sufficiently large to be found by the naked eye and (iii) it points towards the location of the mite and its products. Examination of patients' palms to look for this sign is a simple and efficient way to make a diagnosis of scabies throughout the course of an infestation.