You are describing formaldehyde-induced onycholysis (separation of the nail plate from the nail bed). Once separation occurs there is a warm, moist space beneath the nail plate where things like yeast, bacteria, and fungus like to grow. It is important to keep the nail clipped short and to avoid filing. It is also important to avoid using any nail cosmetics during the healing phase so that the chemicals in the products do not come into contact with the delicate unprotected nail bed that no longer has a firmly attached nail plate to protect it. Your client should wear gloves with any wet work.
— Dana Stern, M.D. is a board-certified dermatologist specializing in nails. She works in private practice in New York City.