Which of the following can result in excessive skin growth due to repeated friction?

Keratomas are localized growths on the skin that occur as a response to repeated friction or pressure. When the skin is subjected to consistent irritation, it may react defensively by thickening, resulting in the formation of a keratoma. This process illustrates the skin's ability to adapt to external stressors, leading to an accumulation of keratin, the protein that forms the outer layer of the skin.

In contrast, dermatitis is a broader inflammatory condition that does not specifically result from friction alone, and while it can cause irritation and changes in skin texture, it does not typically lead to the same type of excessive growth as seen with keratomas. Fungal infections usually manifest as rashes or lesions but are caused by pathogens rather than physical stress. Psoriasis is an autoimmune condition characterized by rapid skin cell proliferation, leading to scaly patches, but it is not directly a result of friction-related stimuli. Therefore, keratoma is the most appropriate answer, as it directly links excessive skin growth to repeated friction.