Researchers examined ear‑canal itching and measured the antimicrobial peptide LL‑37. They found more inflammation than in healthy ears but no extra LL‑37, indicating the itching isn’t caused by dermatitis or LL‑37 deficiency.

This study aimed to demonstrate the histological and immunohistological features of skin biopsy specimens from patients complaining of isolated itching of the external auditory canal. A prospective, case-control study was performed of 24 patients undergoing evaluation for contact dermatitis of the external auditory canal, and 24 controls. Skin biopsies were examined histologically by a single, blinded dermatopathologist, using light microscopy, to determine histopathological characteristics. The immunohistological presence of the antimicrobial peptides human β-defensin-3 and LL-37 cathelicidin was also assessed. Findings for patients and controls were compared. There was a statistically significant difference in the degree of inflammation, comparing patients and controls (p < 0.05). There was no significant difference in the presence of spongiotic changes, comparing patients and controls (p > 0.05). Furthermore, the patients' skin biopsies did not show pronounced expression of human β-defensin-3 or LL-37 cathelicidin. Histological and immunohistological examination of skin biopsies from cases of isolated itching of the external auditory canal did not support a diagnosis of dermatitis.