Is laterality of malignant otitis externa related to handedness?

Malignant otitis externa (MOE) usually affect patients with systemic diseases, especially diabetes mellitus. MOE is a mainly unilateral disease. Given that around 90% of human adults are right-handed we hypothesized that hand preference might be one of the factors involved in the development of MOE. All 38 of the patients whom we treated for MOE between August 2009 and November 2012 (28 males and 10 females, age range 43-91 years) had poorly controlled diabetes mellitus, and all of them reported itching in the involved ear. The difference in the laterality of MOE among our right- and left-handed subjects was significant: right hand dominance was associated mostly with right-sided MOE (24/34) and left hand dominance was associated with occurrence of MOE only in the left ears (4/4, p=0.006). These findings point to an unexpectedly strong relationship between the patient's handedness and laterality of his/her MOE, leading us to hypothesize that the development of MOE might be attributable to self-inflicted local trauma to the ear canal on the same side as the dominant hand.