Causes and risk factors
Melanonychia is caused due to excess production of melanin, which is secreted by melanocytes. Melanocytes lie dormant in nail matrix. Melanocytic activation and melanocytic hyperplasia results in melanonychia. Melanocytic activation is an increased production of melanin; however, the number of melanocytes is normal. The melanin is deposited in keratinocytic cells of the nails. While melanocytic hyperplasia refers to an increased production of melanin along with increase in the melanocytes, this hyperplasia can either be benign or malignant. Various skin conditions like lichen planus, psoriasis, scleroderma, or fungal infections or a variety of infections of the nails itself can also lead to discoloration of the nails. Systemic diseases like malnutrition, Nelson syndrome, Cushing syndrome, porphyria, or vitamin B12 deficiency are also other causes. Melanonychia is commonly seen as a side effect caused due to administration of chemotherapeutic agents used for treating cancers. Various syndromes have been associated with this conditions, the common among them are Touraine syndrome and Peutz-Jeghers syndrome. Poor fitting shoes, trauma, foreign body, or ultraviolet radiation are the other contributing factors.
Clinical presentation:
The symptoms are more prominently seen in dark complexioned people. Some patients may remain asymptomatic while a few can present with complaints of brownish black discoloration of the nails. One or all the nails can be affected. Longitudinal lines are seen or the entire nail can be affected. These bands of discoloration can measure 3 mm or more. These lines extend from the cuticle to the free edges or they can be seen transversely. Along with this, thickening of the nails and arrested nail growth can be seen. The nails become brittle and they break off easily.
Investigations
The diagnosis is done on the basis of the symptoms narrated by the patient and physical examination carried out by the dermatologist. Dermoscopic examination along with nail biopsy is the diagnostic investigation here.
Treatment
As in most of the cases, melanonychia is caused due to certain underlying diseases, and treating the underlying cause is the main line of treatment. If certain medications have induced this condition, those need to be stopped immediately. However, in cases where a melanoma of the nail is suspected, complete excision of the nail is required. Surgical intervention needs to be adopted in cases of invasive melanoma.
Other modes of treatment:
Certain other modes of treatment can also be helpful in coping up with the disease. Taking into consideration the symptoms in a holistic way, homoeopathy can offer a good aid for the relief of the symptoms. The Ayurvedic system of medicine which uses herbs and synthetic derivates can also be beneficial in combating the complaints.
