Change in nail color: causes, symptoms, diagnosis, treatment

Changes in the color of the nail plate (chromonychia) can occur due to exogenous staining of the nail and can be associated with a number of endogenous factors that affect the color of the nail plate. Color changes to white, yellow, green, blue, red (purple), brown (black) are distinguished.

Leukonychia (white coloration) is divided into true and apparent. Dysfunction of the nail matrix leads to the development of true leukonychia, and apparent reflects the state of the microcirculatory bed. White transverse stripes or white dots are characteristic of impaired maturation and keratinization of onychoblasts and are found in neurocirculatory dystonia, hypo- and avitaminosis, familial benign pemphigus Gougerot-Hailey-Hailey, nail trauma. Onychodystrophy should be distinguished from white superficial onychomycosis, in the clinical picture of fungal infection, superficial white foci can be combined with striation of the nail.

In addition, apparent leukonychia can be recorded in anemia, liver cirrhosis, chronic renal failure, nephrotic syndrome, acute poisoning, shock of any etiology.

Yellow nails are more common in onychomycosis. A characteristic sign is a change in the color of the affected area of the nail. The yellow color of the entire nail plate can be caused by a number of endogenous and exogenous factors. In particular, with jaundice of any etiology, a change in the color of the nail plates can be the earliest manifestation of the disease, along with hysteria of the sclera and mucous membranes. Yellow nails are also characteristic of carotenoderma, and can occur when taking a number of medications. A combination of thickening of the nails with yellow coloring of the entire surface of the nail plate is diagnosed in chronic lymphostasis (yellow nail syndrome) and in erythroderma of various origins. Long-term use of decorative nail polishes without preliminary application of a "base" coating to their surface also leads to yellow coloring.

Red (purple) coloration of the nail (erythronychia) is a reflection of the state of microcirculation in this area. Thus, diffuse reddish-cyanotic coloration is characteristic of venous stasis and occurs in heart failure in combination with acrocyanosis and cyanosis of the lips. In case of insufficient arterial blood circulation in the distal phalanges of the fingers, there is an uneven pinkish-red coloration above the lunula of the nail. In addition, erythronychia is characteristic of psoriasis, lichen planus, secondary amyloidosis, Darier's disease, bullous epidermolysis. In case of psoriasis, in the case of a subungual papule, there is also onycholysis. Erythronychia can be a sign of neoplasms in the nail bed (hemangioma, glomus tumor, enchondroma, etc.). This symptom can be expressed in diseases of the hematopoietic system, vasculitis and disorders of coagulation and hemostasis (for example, hemophilia, thrombocytopenia, taking anticoagulants). Subungual post-traumatic hematoma in the early stages can lead to purple-red coloration of the nail.

Brown (black) color of the nail (melanonychia) is caused by a number of induction agents (dermatophyte fungi, yeast-like fungi, Proteus, etc.). Exogenous nail staining is possible when using various external preparations (silver nitrate, dithranol, potassium permanganate), decorative coatings and when in contact with tobacco. Melanonychia often occurs in dark-skinned and swarthy-skinned people, i.e., those belonging to phototypes V and VI, and has been described during pregnancy. Such staining is also characteristic of melanocytic formations in the nail bed area (nevi, melanoma). The initial manifestations of melanoma in the area of the terminal phalanx of the finger are characterized by the involvement of only one finger in the process, unclear boundaries of the lesion, beginning from the lunula area, gradual spread of pigmentation to the periungual fold and finger pad. A distinctive feature of melanonychia in melanoma is the lack of dynamics of nail color change as the nail plate grows. Longitudinal melanonychia (a longitudinal stripe on the nail plate) can be a sign of some ethnic characteristics, vitiligo and has been described in HIV-infected patients against the background of long-term use of various medications.

The green color of the nail plate can be caused by the evolution of a subungual hematoma, and occurs in infectious, often bacterial, processes caused by coccal microflora, Pseudomonas aeruginosa, etc.

Blue (gray) discoloration of nails is typical for patients with argyria and occurs with long-term use of a number of medications, including antimalarial drugs, minocycline, phenothiazides, etc. In dermatological practice, a similar change in nail color occurs when using solutions containing copper sulfate in external therapy.

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