A high percentage of the population suffers from onychomycosis, fungal infection of the nail is considered a public health problem. Fortunately, there are effective treatments that only need perseverance and patience to succeed.
Applicable, before speaking directly to the disease in question, is to mention some features of the nails, which are considered attachments of the epidermis (outer layer of skin) that are composed mostly of keratin.
Nails are regenerated throughout life, and it is known that a fingernail grows, on average, between 0.5 and 1.2 mm per week, whereas those of the feet increase in size more slowly, at half of the speed of the fingernails.
However, the nails of the upper limbs take about 5.5 months to develop from its parent (source), while toenails require 12 to 18 months, remember that the speed of nail growth slows as older.
Onychomycosis is a highly contagious infection caused mainly by a fungus called dermatophytes (the most common varieties are Trichophyton rubrum and Trichophyton mentagrophytes), whose favorite food is keratin, the basic substance of the nail.
The disease occurs when spores of the fungus, which in principle remain in the folds and furrows of the skin, are trapped at the free edge of the nail (zone in which dirt or debris deposits), which is worth a moisture-filled habitat to establish the infectious process.
Note that the condition in question may affect the hands and feet simultaneously or separately, and is estimated that from fifteen to twenty percent of the population between 40 and 60 years of age suffer from this condition, in exceptional circumstances it may acquire children.