A toenail turns slightly yellow at the tip. Over a few months it thickens, then starts to crumble at the edge. It might lift away from the nail bed. It gets harder to cut. Eventually you stop wearing open shoes.

Most people live with this for years. It is not painful, so it stays on the list of things to deal with later — and the one paint from the chemist that did nothing convinced them it can’t be fixed.

It usually can. But the first job is not treatment. It is finding out what you are actually dealing with.

Thick, yellow, crumbling nails: what’s actually going on

Fungal nail infection — onychomycosis — happens when fungus gets into the nail bed underneath the nail plate. It thrives there because it is warm, dark and often damp, and because the nail itself shields it from anything you put on top.

That last point explains why so many treatments fail. The infection is under the nail. Painting the surface rarely reaches it.

It usually starts at the free edge or the side of the nail and works backwards toward the cuticle. Common signs:

  • Yellow, white or brownish discolouration
  • Thickening, so the nail is difficult to cut
  • Crumbling or flaking at the edge
  • The nail lifting away from the nail bed
  • A slightly musty smell
  • Often the athlete’s foot came first — the skin infection usually precedes the nail one

Toenails are affected far more often than fingernails, and the big toe most of all.

Who gets it, and why it’s more common than you’d think

Fungal nail infection becomes more common with age — partly because nails grow more slowly over time, so the fungus gains ground faster than the nail can push it out.

Beyond that, the risk factors are mostly about environment and opportunity:

  • Closed shoes for long hours. A warm, enclosed, slightly damp shoe is close to an ideal growing environment. Anyone in formal work shoes five days a week is a candidate.
  • Gyms, pools and shared showers. Fungal spores survive well on wet floors, and bare feet pick them up readily.
  • Existing athlete’s foot. This is the most under-appreciated one. The skin infection almost always comes first and then migrates into the nail. Treating a nail while ignoring the skin between the toes is why so many people relapse.
  • Nail trauma. A nail damaged by running, football or shoes that pinch gives fungus an entry point. This is why runners so often have one affected big toenail and nine healthy nails.
  • Shared nail tools. Clippers and files carry infection between people — and between your own nails.
  • Diabetes and reduced circulation, which we cover further down.

None of this is about cleanliness. It is about warmth, moisture and opportunity — and almost everyone encounters all three.

Before anything else: is it definitely fungus?

Here is the part that changes how you should think about this.

A substantial proportion of nails that look fungal are not fungal at all. Studies consistently find that a large share of clinically diagnosed onychomycosis turns out negative when actually tested. Several other conditions produce a thickened, discoloured nail.

Could also be The tell
Nail psoriasis Tiny pits in the nail surface, an oily-looking brown patch, often psoriasis elsewhere
Old trauma One nail only, often the big toe, in a runner or someone who wears tight shoes
Chronic paronychia Swollen, tender skin around the nail fold; common in people whose hands are wet all day
Lichen planus of the nail Thinning and ridging rather than thickening; can scar the nail permanently
Bacterial infection Greenish-black discolouration, often Pseudomonas
Subungual melanoma A dark band running lengthwise, especially if it widens or the pigment spreads onto the skin

That last row is the reason we do not treat nails by eye alone.

Why we test before we treat

Oral antifungal tablets are effective. They are also a commitment: six weeks for fingernails, three to six months for toenails, and they are processed through the liver, so treatment usually involves blood monitoring.

Committing to months of tablets for a nail that was never fungal is a bad trade. It delays the real diagnosis and puts you through medication you didn’t need.

So we take a nail clipping and some debris from under the nail and send it for testing. It is painless, takes a minute, and the result tells us whether we are treating fungus, and often which type.

If the diagnosis is unclear even then, a skin biopsy can settle it.

How fungal nail infection is treated

Once we know what we are treating, there are three tools, usually used together.

Approach Best for How long What to expect
Debridement Almost all cases, alongside other treatment Repeated as the nail grows Thick nail thinned so treatment can reach the bed
Topical antifungal Mild cases, the tip only, 1–2 nails 6–12 months Slow, needs real consistency
Oral antifungal Moderate to severe, several nails, big toe 6 weeks (fingers) / 3–6 months (toes) Most effective route; needs blood monitoring

Nail thinning and debridement

Reducing the thickness of the nail does two things: it makes the nail comfortable and easier to manage, and it removes the barrier that was stopping topical treatment from reaching the infection. Where there is diseased material under the nail, clearing it away meaningfully improves how well everything else works.

Topical treatment

Medicated nail lacquers and solutions can work for early, limited infection — where only the tip is involved and only one or two nails. They are slow, because they only really work as the new nail grows out, and they need applying consistently for months. We are honest with you about whether your nail is a realistic candidate.

Oral antifungal tablets

For anything more than mild, tablets are the effective route. They work from the inside, reaching the nail bed through the bloodstream. You will not see a normal nail at the end of the course — you will see healthy nail growing from the base while the damaged part grows out. A toenail takes roughly nine to twelve months to fully replace itself, so patience is part of the treatment.

We will also usually treat any athlete’s foot or skin fungal infection at the same time. Treating the nail while leaving the skin infection is how people end up reinfected.

A dark line under your nail: when to get it checked

This section is short and it matters.

A brown or black band running lengthwise down a nail is called longitudinal melanonychia. In people with deeper skin tones it is common and usually completely benign — often several nails, symmetrical, stable over years.

But the same appearance can be the first sign of subungual melanoma, a rare cancer of the nail unit. And it is diagnosed late in Black patients far more often than it should be, partly because benign pigmented bands are so common that the serious ones get dismissed.

Get a nail band looked at if:

  • It appears on a single nail, especially the thumb or big toe
  • It is getting wider, particularly wider at the cuticle than at the tip
  • The colour is uneven — varying shades of brown and black within the band
  • Pigment spreads onto the surrounding skin or the cuticle
  • The nail is splitting, cracking or deforming along the band
  • It is new in adulthood without any injury

This is not a reason to panic — the overwhelming majority are harmless. It is a reason to have it examined properly rather than watched anxiously for another two years.

Nail changes that aren’t infection at all

Worth knowing about, because they get treated as fungus for years:

  • Nail psoriasis — pitting, ridging and an oily discolouration. It responds to treatment for psoriasis, not antifungals.
  • Trauma — one damaged nail, often from running or narrow shoes. It just needs time and protection.
  • Chronic paronychia — inflammation of the skin around the nail, common in people whose hands are constantly wet.
  • Ingrown toenails — a different problem with a different solution. See ingrown toenail surgery.

If you have diabetes, read this bit

Nail and foot fungal infection matters more if you are diabetic. Thickened nails press on the nail bed and can break the skin. Reduced sensation means you may not feel it. And a small break in the skin of a diabetic foot is not a small thing.

If you have diabetes and a thickened or discoloured toenail, please have it assessed rather than left. Nail care in this situation is preventive medicine, not cosmetics.

Stopping it coming back: a checklist

Reinfection is the main reason people conclude treatment “didn’t work”. While you are being treated and afterwards:

  • Treat the skin as well as the nail — athlete’s foot is the usual reservoir
  • Wear flip-flops in gym showers and around pool decks
  • Dry between your toes properly, every time
  • Rotate your shoes so each pair dries out fully between wears
  • Antifungal powder or spray inside shoes during and after treatment
  • Your own clippers and file — and don’t use the same tool on a healthy nail after an infected one
  • Be careful at the pedicure — take your own tools, or use a salon that sterilises properly
  • Finish the full course, even though the nail still looks wrong. It will, for months.

What your first appointment looks like

  1. We examine all twenty nails, not just the one bothering you — the pattern is informative.
  2. We take a clipping for testing if fungal infection is the likely diagnosis.
  3. We debride the nail where it is thickened, which usually brings immediate comfort.
  4. We discuss options honestly, including whether tablets are worth it for your situation.
  5. We arrange blood tests if oral treatment is planned.

Appointments run from 8:30am to 5:00pm on weekdays, and 9:00am to 4:00pm on Saturdays.

Getting to the clinic

We are on the 2nd floor of Landmark Plaza, Argwings Kodhek Road, on the Hurlingham edge of Upper Hill.

Frequently asked questions

How long does it take to clear a fungal toenail? The infection is usually cleared within the treatment course, but the appearance takes longer, because you have to grow out the damaged nail. A toenail replaces itself over roughly nine to twelve months. Fingernails are quicker, around four to six.

Do I really need tablets? Can’t I just use a paint? For a mild infection at the tip of one or two nails, topical treatment is reasonable. For thickened nails, several nails, or the big toe, topical alone rarely succeeds. We will tell you which situation you are in rather than selling you the easier answer.

Are the tablets safe? For most people, yes. They are processed by the liver, so we check your liver function before and sometimes during treatment, and we review any other medicines you take. That monitoring is exactly why this belongs with a doctor rather than over a counter.

Why test if you can see it’s fungus? Because a large share of nails that look fungal aren’t. Testing takes a minute and prevents months of unnecessary medication.

How much does fungal nail treatment cost in Nairobi? It depends on how many nails are involved and whether you need topical or oral treatment plus monitoring. Call 0728 566990 for a straight answer. Fees are quoted before your appointment, and most medical insurance schemes are accepted.

Is it contagious? It can spread — to your own other nails, and to other people through shared surfaces, towels and nail tools. It is not highly contagious through casual contact.

I have a dark line down one nail. Should I worry? Most are harmless, particularly if several nails have them and they have been stable for years. But a single new band that is widening, uneven in colour, or spreading onto the skin should be examined. Please book rather than wait.

Can I still wear nail polish? During treatment, generally no — it blocks topical treatment and hides what we are trying to monitor. Once things are growing out well, we can revisit it.

Will it come back? Recurrence is common, mostly through reinfection from skin or footwear. The checklist above is genuinely the difference between clearing it once and clearing it for good.

Book an appointment

If a nail has been thickening quietly for a year, it will not turn around on its own — and if it is something other than fungus, the sooner that is known the better.

We open at 8:30am Monday to Friday and 9:00am to 4:00pm on Saturdays.

Landmark Plaza, 2nd Floor, Argwings Kodhek Rd, Nairobi
Call or WhatsApp 0728 566990
info@skinbydrnancy.com

Book an appointment or browse all dermatology services.