Nail changes often occur in Graves’ disease during periods of active hyperthyroidism. In general, finger and toenails grow rapidly in hyperthyroidism, causing them to appear thin and brittle with jarred, ragged margins at the white tips. The nails may also appear pitted and discolored.
Patients with Graves’ disease may also develop onycholysis or Plummer’s nails, which can cause the margins at the nail whites to appear discolored and dirty. Plummer’s nail can also cause the distal nail body to separate from the nail beds, making the nail appear raised away from the cuticle. Dirt tends to accumulate near this separation. Onycholysis, for unknown reasons, is most likely to occur in the fourth finger.
Onycholysis is not specific for Graves’ disease. It may occur in conditions of psoriatic arthritis, lung cancer, sarcoidosis, bronchiectasis, trauma, chronic arthritis, and syphilis. Medications that may induce onycholysis include tetracyclines, fluoroquinolones, chloramphenicol, and chemotherapeutic agents such as bleomycin, paclitaxel, and 5-fluorouracil.
Nail changes that occur in hyperthyroidism tend to resolve quickly when thyroid hormone levels return to the normal or reference range.