Changes in the shape of nails: causes, symptoms, diagnosis, treatment

The most common variations in the shape of the nail plates are koilonychia and convex watch-glass nails.

Koilonychia is a special type of onychodystrophy, manifested by concave nails. Small thickness or thinning of the nail plate is a common cause of all koilonychia. Koilonychia occurs in newborns, children of the first year of life and in individuals with congenital ectodermal dysplasia. The thickness of the nail plate is affected by chronic iron deficiency, hemochromatosis, long-term infectious diseases. Thinning occurs with systematic chemical exposure to the nail (contact with chemicals in production and at home, the use of decorative coatings and nail polish removers with a high acetone content, long-term wearing of artificial nails, etc.). Koilonychia is a characteristic symptom of lichen planus, to a lesser extent - for psoriasis and onychomycosis.

Watch-glass nail dystrophy, which often occurs on the nail plates of both hands or on all nail plates, is usually caused by chronic lung and bronchial diseases. The mechanism of its development is associated with changes in microcirculation in the nail bed area. Watch-glass nail dystrophy is a symptom of diseases such as bronchiectasis, chronic pneumonia, pulmonary emphysema, pulmonary tuberculosis, bronchogenic lung cancer, pneumocystis pneumonia compensated for a long time by drug treatment, etc. Watch-glass dystrophy is often combined with hypertrophy of the tissues of the terminal phalanges of the fingers and the formation of so-called clubbing. However, in addition to diseases of the respiratory system, the development of the specified symptom complex can also be caused by diseases of the cardiovascular system (compensated and subcompensated heart defects, benign tumors of the atria and ventricles, leading to hemodynamic disorders), gastrointestinal tract (liver cirrhosis, chronic active hepatitis, Crohn's disease, nonspecific ulcerative colitis, bowel cancer, etc.), endocrine system (autoimmune thyroiditis). In case of asymmetric nail damage on only one limb, osteochondrosis should be diagnosed. Compression of the vascular-nerve bundle is also likely with spinal trauma, damage to the brachial plexus, aortic or subclavian aneurysm, as well as with enlarged lymph nodes (tuberculosis of the intrathoracic lymph nodes, cancer, metastatic processes) and as a result of adhesive processes.

A "watch glass" lesion of one nail plate may be caused by benign or malignant formations in the nail bed area (mucous cyst of the tendon sheath, glomus tumor, angioleiomyoma, basal cell carcinoma, etc.). Cosmetologists and pedicure specialists are not recommended to apply special staples to the nail plate in order to level its surface without a preliminary analysis of the causes of "watch glass" onychodystrophies, since early diagnosis and timely treatment are important for these diseases.

There are other variants of nail shape changes. Ingrown nails, as well as improper removal of a nail or part of a nail plastic surgery, can significantly change their shape, both in the area of the hands and feet. A peculiar change in shape is also possible, which is usually called a racket-shaped nail. With this variant of onychodystrophy, the nail plate is sharply shortened and widened. As a rule, the first fingers of the hands are affected symmetrically, and cases in families are not uncommon. This condition is based on congenital shortening of the terminal phalanx of the fingers. The specified onychodystrophy can occur in the distal form of psoriatic polyarthritis as an acquired variant of a racket-shaped nail. With this pathology, the shortening of the phalanx is due to the severity of joint damage and osteoporosis.

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