You can get infected with a fungus in a shoe store, if a couple before you has tried on a person who has such a disease, in the shower, bath or pool. Due to inadequate treatment, the disease can progress rapidly enough.
At the initial stage, many patients are unaware of the problem, since there is no pain and discomfort, and the appearance does not say much. Therefore, the severe form of mycosis is not so rare. Fortunately, it is treated, you just need to be patient.
Before treatment:
It is important to eliminate the cause of severe mycosis. It can be a constant visit to a public bath without your slates or, for example, using someone else's shoes at work. Anything that can contribute to infection should be ruled out.
You should always remember hygiene - keep your feet clean and dry, wear clean socks every morning, keep the house clean. Sometimes it seems that all this is trifles, but in fact it is hygiene that avoids infection. After the course of treatment, all footwear should be disinfected .
To maintain immunity, you should drink vitamins, eat healthy food and give up harmful habits.
Finally, treatment should be continuous. You can not forget to take pills and apply local medications, otherwise all treatment will fail.
Treatment of a nail fungus of a neglected form requires an integrated approach. At this stage it is impossible to recover using only the drug for external use (ointment or lacquer, for example), a complex of medicines is needed:
Systemic agents ( tablets for oral administration).
Mechanical removal. This can be a neat cutting / cutting off of the damaged part of the nail, a medical pedicure in the hospital or a suitable preparation for softening the nail.
Common restorative drugs (multivitamins are mandatory) and the means that activate immunity.
Let us consider specific examples from medical practice:
1. The nail on the big toe is struck. The patient turned to the clinic after the part of the nail had collapsed.
A sample was scraped and sown. Infection with dermatophytes was revealed.
Orungal tablets are prescribed for courses of 1 week, a break between courses is 3 weeks, only 3 courses.
In the first 3 months, Exodermil droplets were prescribed, after which there was a significant improvement, the damaged part of the nail was removed by the patient independently. This was done with the help of a nail file, gradually, before each application of drops.
After that, the patient was transferred to Loceril lacquer, applied once every 2 weeks. Before each application, the remnants of the old varnish were removed.
In just six months, a significant improvement is noticeable (bottom photo). It is advisable to continue applying the varnish for another six months, disinfecting shoes and living quarters, a multivitamin treatment every 2 months.
2. A similar case, with the exclusion of the causative agent, is a family of yeast-like fungi.
Lamizil tablets are prescribed for courses of 2 weeks, a break between courses 4 weeks, only 2 courses.
Several machining procedures were performed in the clinic with a special lacquer applied, after which a significant portion of the nail was removed. In parallel, the patient applied antifungal drops daily.
The second photo was taken after 8 months, markedly improved, not as rapid as in the first case, in view of the patient's more solid age.
It is recommended to apply an antifungal lacquer and further supervision by a doctor.
Here's another good example, varnish + pills courses:
You can get infected with a fungus in a shoe store, if a couple before you has tried on a person who has such a disease, in the shower, bath or pool. Due to inadequate treatment, the disease can progress rapidly enough. 
1. The nail on the big toe is struck. The patient turned to the clinic after the part of the nail had collapsed. 
2. A similar case, with the exclusion of the causative agent, is a family of yeast-like fungi.