Toenail fungus (onychomycosis)
Thickened, yellow, or brittle nails. We explain how we confirm if it is fungus and how we treat it.

The full guide
What is it?
In summary: before months of treatment, we confirm that it really is a fungus —not every thickened or discolored nail is one. With a clear diagnosis, we plan it consistently. Podiatric treatment in Martorell, Barcelona and Igualada.
Onychomycosis is the infection of the nail by fungi. It causes the nail to thicken, change color (yellow, brown) and become brittle. It is very common and difficult to treat because the fungus is stubborn.
One piece of advice before months of treatment: confirm that it is a fungus. Not every thickened or discolored nail is one, and treating the wrong thing only wastes time.
Why nail fungus is so hard to eliminate
The fungus lives inside and under the nail plate, a hard structure where treatments reach with difficulty. Furthermore, the toenail grows slowly: even if the treatment works, the damaged part does not “heal,” but rather must be replaced by new, healthy nail. This is why treatment is long by definition, and consistency is as important as the product.
There is another factor that plays in favor of the fungus: its ideal habitat is your footwear. Heat, moisture, and darkness. If the nail is treated but habits are not changed —socks, drying, footwear hygiene— reinfection is served.
In consultation, chiropody plays a key role: debriding and reducing the thickened nail helps the treatment penetrate and leaves the fungus with less ground.
Fungus or trauma: not every ugly nail is onychomycosis
This is the most frequent trap. A yellow, thick, or lifted nail can be a fungus… or the result of repeated microtraumas (tight footwear, sports), psoriasis, or simply a nail damaged years ago that no longer grows well.
From the outside they can look almost identical. And treating a nail that does not have fungus with antifungals for months is wasting time and money. Therefore, in case of doubt, we perform a confirmation test before starting any long plan.
A practical detail: a nail thickened by fungus also digs into the skin more easily. If you feel pain on the edge of the toe, an ingrown toenail may have been added, and then the treatment plan changes.
How to avoid contagion at home and in the locker room
Onychomycosis is contagious, but with simple habits the risk drops significantly:
- Flip-flops in public showers, pools, and locker rooms.
- Dry feet well after showering, also between the toes.
- Breathable socks and daily change; alternate pairs of shoes so they dry out.
- Do not share nail clippers or files; disinfect them if someone at home has fungus.
And one group that must take special care: people with diabetes. In the diabetic foot, a fungal infection can open the door to complications, and any change in the nails should be reviewed early.
If several people live together and one has fungus, treating it early also protects the rest: the less time the infection is present, the fewer opportunities for contagion there are.
How it feels
Symptoms
Thickened, yellow, or brownish nail
Brittle nail or crumbling at the edge
Sometimes, separation of the nail from the bed
Why it happens
Causes and risk factors
It is caused by fungi that take advantage of the moisture and heat of footwear. It is contagious and persistent: therefore, before treating for months, it is advisable to confirm that it really is a fungus and not another nail alteration.
At the clinic
How we diagnose it
01
Examination
We assess the appearance and extent of the nail.
02
Confirmation
If necessary, a test is performed to confirm that it is a fungus.
Don’t let it linger
When to see us
If a nail changes color, thickens, or crumbles and does not improve, it is worth having it assessed. The sooner it is treated, the easier it is; and confirming the diagnosis avoids months of useless treatment.
Muy profesional y buen trato, tanto para mí como para mi hija. Las plantillas van genial. Lo recomiendo.
Carlos C. · Google review
Frequently asked questions
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