SUBUNGUAL EPIDERMOID INCLUSIONS

SUMMARY.— This paper describes the evolution of subungual epidermoid inclusions and discusses their aetiology. They are shown to develop from the tips of the rete ridges by a process of bulbous proliferation. Ultimately they may lose their connection with the epidermis and come to lie deeply within the dermis of the nail bed. Although the lesions are usually microscopic in size they may be large and should be considered in the differential diagnosis of nail bed swellings.

The aetiology of these lesions is still obscure. They may follow trauma and are found in finger clubbing and it is probable that different stimuli can produce them.