Which of the following disorders is associated with pterygium of nails?

When Lichen planus affects the nails, it causes scarring of the nail bed with early nail ridging and splitting later leading to pterygium formation. Pterygium of nail is scarring from the base of the nail outward in a V formation, which leads to loss of nail. Nail changes in psoriasis includes presence of irregular pits, oil spots, separation of nail plate from its bed, thickening and crumbling of nail plate. People with alopecia areata people have regular nail pits that form a pattern. Ref: Harrison's Principles of Internal Medicine, 18th Edition, Chapter 52; The Merck Manual Home Health Handbook By Merck; The Landscape Makeover Book By Sara Jane Von Trapp, Page 122.