What is the yellow growth between the fingernails of my foot called?

Hello,

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Thank you for your query. As per the history and image provided (attachment removed to protect the patient's identity), the condition is callus or corn formation, which can form due to footwear. It is common and can be painful. There are treatments available. It is a slow process, but the thickness will reduce with time. Callus or corn is formed due to thickening of the skin in that particular area either due to constant friction with footwear or with the floor and may be seen in weight-bearing areas and sometimes on the upper part of toes as well. It does not spread within our body or from one person to another. The idea of the treatment is to reduce the thickness of the lesion. So, I suggest you to follow the instructions mentioned below. Salicylic acid and lactic acid solution (Watnil solution) to be applied to the lesion in a single drop every night. Once the solution is applied, place a plaster with a cotton in the center (to avoid sticking the adhesive part of the plaster directly on the lesion as peeling it may be painful) of the lesion. The surrounding area of the lesion may be secured by applying vaseline to prevent the normal skin from being affected by the solution. The following day, remove the plaster, wash the area well, and soak your foot in warm saline water for ten minutes. Use a pumice stone or a nail filer and gently scrub the top layer of the lesion, do not over scrub as the same process needs to be repeated daily. Repeat applying vaseline and Watnil solution at night on the affected area. Also repeat plastering, soaking, and gently scrubbing the following day. Repeat the same for four weeks or until there is a reduction in the lesion size and the thickness. Wear soft and comfortable footwear at home and while going out. Moisturize your foot daily to avoid the same in the future. I hope this has helped you. Thank you.