(Atrophy of the nails; Onychotrophia)
Definition. A condition of the nails characterized by their decreased size or thickness, softening, splitting, crumbling and discoloration.
Symptoms. This condition may be congenital or acquired. The former variety is rare, is usually found upon fingers or toes congenitally deformed and is associated with defective hair growth. Absence of the nails (anonychia) sometimes occurs in these cases and when the fingers are distorted or webbed the nails are naturally misformed. Acquired atrophy is more common and may affect all or part of one or two nails, rarely more. The affected nail is grayish- white, lusterless, either uniformly or in stripes or specks. It is smaller and thinner than normal, with soft and delicate nail substance like a thickened membrane. It may be rough and irregular from longitudinal exfoliation or fractures, or it may be granular or worm-eaten in appearance. A number of varieties are distinct enough to warrant a brief description.
Spoon nails is the term applied to a condition associated with wasting disease, although it is occasionally idiopathic. The nail is thinned with surface concavity from side to side. Everted edges and an occasional anteroposterior concavity completes its resemblance to the bowl of a spoon. The condition may spread gradually from one nail to another but is never found on the toes.
Reedy nails are so called because of the prominence of the normal longitudinal marking occurring upon atrophy of the intermediate nail substance, giving a striated appearance. It has been regarded as a senile change and as due to gout or rheumatism.
White nails (leucopathia unguium) is frequently observed in nails otherwise healthy as spots or transverse bands of a dead white color. These are first seen at the lunula and grow forward until finally cut off.
Etiology and Pathology. The same factors that are held to be responsible for nail hypertrophy may cause atrophic changes. Thus, traumatisms, vegetable parasites, chronic scaling or inflammatory skin diseases, nervous disorders and heredity are all etiological. White nails are due either to febrile diseases, nervous disorders or local traumatisms. Their appearance is supposed to be caused by the presence of air in the nail substance, although some believe the condition is a trophoneurosis causing nutritional changes in the nail matrix.
Prognosis and Treatment. The former depends entirely upon the causal factors and their discovery. Treatment is practically the same as described for hypertrophy of the nails. Thus, improvement of local and general nutrition and protection of the parts from traumatisms, water, other liquids and irritating substances are essential. Some mild stain may be employed to reduce the blemish of white nails and the application of a saturated solution of boric acid and any of the milder ointments suggested for eczema might benefit. Atrophy of the nails caused by the ringworm or favus fungus will be considered later. The following remedies have proven useful: Helleb. nig., Hypericum, Kali sulph., Mercurius viv., Silicea, Spigelia and Thuja.