Role of pH of External Auditory Canal in Acute Otitis Externa.

Prospective and interventional. We studied the pH of external auditory canal (EAC) in normal individuals and patients with acute otitis externa (AOE), its variation with change of temperature and humidity, different symptoms and number of symptoms at presentation (Day 0) and various stages of treatment in 100 normal ears and forearms and 50 ears having AOE. The mean pH of normal EAC was 3.950 ± 1.199 while that of forearm was 4.775 ± 0.910. There was increase in the number of patients with increase in relative humidity, however, the change in the pH of EAC was statistically not significant (p > 0.05). Significant fall in pH was observed at 1 and 2 weeks of treatment. The normal EAC pH is relatively more acidic as compared to that of forearm skin and it became more alkaline in cases of AOE with reversion back to acidic pH after treatment. Acidification of the EAC is the only treatment required in most cases. No significant change in pH of ears was observed with changes of temperatures and humidity.