Dr Shavelson has published articles on Fungal Toenails. He is a consultant to pharmaceutical and laser companies working with Ugly Toenails. He has one of the busiest and most successful programs in New York City that is known for its fair pricing. These infections often start out as a white or yellow spot under the tip of your big toenail. Over time deeper these opportunistic plants spread deeper and to other toes if they are not treated and killed. As the nail fungus spreads deeper into your nail, it may cause your nail to discolor, thicken and develop crumbling edges, an unsightly and potentially painful problem.