Differential Diagnosis in Primary Care
4th Edition

Nail Changes
There are various types of nail changes, such as thickening (onychogryposis), thinning, deformity, and separation from the nail bed (onycholysis). Whenever a peculiarity of the nail exists, the mnemonic VINDICATE will help to recall all the causes.
  • V—Vascular disease includes the anoxic disorders that cause clubbing (see page 91), iron deficiency anemia that causes spoon nails or koilonychia, Raynaud disease, vasculitis (periarteritis nodosa), and peripheral arteriosclerosis, which causes dystrophy or onychogryposis of the nails.
  • I—Inflammatory diseases that involve the nail bring to mind fungus infections causing onychia (nail bed inflammation), paronychia, syphilis (which can cause almost any nail change), subacute bacterial endocarditis (SBE), and trichinosis, which causes splinter hemorrhages of the nail.
  • N—Neoplasms do not usually cause nail changes, with the exception of clubbing and pallor from secondary anemia. Chondromas, melanomas, and angiomas are a few neoplasms that do. Intestinal polyposis may cause nail atrophy. The N, however, can be used to recall neurologic disorders such as peripheral neuropathy (dystrophy or onychogryposis), syringomyelia, and multiple sclerosis.
  • D— suggests deficiency diseases such as avitaminosis (B2 and D).
  • I—Intoxication includes arsenic (white lines and transverse ridges across the nails) and radiodermatitis.
  • C—Congenital disorders include psoriasis, congenital ectodermal defects, absence of nails (onychia), micronychia, and macronychia.
  • A—Autoimmune disorders suggest scleroderma, periarteritis nodosa, eczema, and lupus.
  • T—Trauma causes the familiar subungual hematoma that turns the nail to turn dark red or black.
  • E—Endocrine disorders are probably some of the most important causes of nail changes. Hypothyroidism produces nail dystrophy, brittleness, and onycholysis; similar changes, plus spooning of the nails, occur in hyperthyroidism. In hypopituitarism, these may be dystrophy, loss of the subcuticular moons, and spooning. Thickening and transverse grooving of the nails may be seen in hypoparathyroidism.
Approach to the Diagnosis
The diagnosis of nail abnormalities begins by correlating the nail changes with other findings (e.g., neurologic and endocrinologic). Laboratory workup depends on the particular disease or diseases suggested by the nail changes (see Appendix A).
Other Useful Tests
  • Complete blood count (CBC) (iron deficiency anemia)
  • Sedimentation rate (chronic infectious disease)
  • Blood cultures (SBE)
  • Trichinella antibody titer (trichinosis)
  • Free thyroxine (FT4) and sensitive thyroid-stimulating hormone (S-TSH) levels (hyperthyroidism, hypothyroidism)
  • Serum parathyroid hormone (PTH) (hypoparathyroidism)
  • Serum growth hormone, luteinizing hormone (LH), follicle-stimulating hormone (FSH) (hypopituitarism)
  • Computed tomography (CT) scan of the brain (pituitary tumor)
  • Chest x-ray (neoplasm, tuberculosis, bronchiectasis)
  • Arterial blood gas (pulmonary disease, heart disease)
  • Hair analysis for arsenic (arsenic poisoning)
  • Antinuclear antibody (ANA) analysis (collagen disease)
  • Glucose tolerance test (diabetic arteriolar sclerosis)
Nail changes