Written By: Chloe Wilson BSc(Hons) Physiotherapy
Reviewed By: FPE Medical Review Board
Yellow toenails are a common problem with a variety of possible causes. Changes in toenail colour usually develop gradually over time.
Yellow toe nails may also be associated with hardening and thickening of the nail, which may also become brittle and prone to breakage.
Yellow toenails may be from something simple such as nail polish, a fungal infection or in some cases may be a sign of a serious underlying medical condition which requires attention. But how can you tell the difference?
There are a number of different things that can cause yellow toenails. Let's have a look at the most common causes of yellow toe nails, what causes them and what other symptoms may be associated with them to help you work out what is going on and what you can do to treat them.
The most common cause of yellow toenails is a fungal infection that attacks the nail, known as onychomycosis. It is often ignored initially as there is little if any discomfort, but the longer it is left untreated, the longer it will take to clear when treatment does finally begin.
Fungal infections tend to be located underneath the nail. It may start with a yellow spot under the nail that gradually spreads through the nail, and some people even develop yellow skin around their nails. Fungal nail infections gradually eat away at the keratin, the protein that makes nails hard and strong. Fungal toenail infections can also be linked with yeast infections elsewhere in the body.
The type of infection tends to vary depending on the climate you live in – in cool, temperate climates yellow nail fungus is typically due to dermatophytes, whereas in hot, humid, tropical environments it tends to be from non-dermatophylic moulds or candida.
In most cases, the first sign of a fungal nail infection is the gradual discoloration of the toenails starting at the edge of the nail and spreading inwards. Eventually, the whole nail turns yellow.
The nails gradually thicken, become brittle and may even break and in some instances there may be a foul smell from the infection.
There may also be some pain or discomfort when pressure is placed on the nails or when wearing shoes. Typically it is the big and little toes that are most affected by fungal nail infections and you often end up with thick nails.
Common causes of yellow toenails from fungal nail infections include:
Fungus thrives in moist, warm, damp conditions so fungal toenail infections are often picked up from walking barefoot in public places such as swimming pools, public showers and gyms.
Yellow toenails from fungal infections are fairly common with approximately 10% of the adult population suffering from onychomycosis at some point in their lives.
Yellow Nail Syndrome is a rare, but serious cause of yellow toenails. There are three typical characteristics with this yellow nail syndrome:
People who present with at least two of these three symptoms are usually diagnosed with yellow nail syndrome. Yellow toenails and/or fingernails are usually always seen in this condition but the colour changes may be quite subtle. Treatment for yellow nail syndrome usually focuses on addressing any lymphedema or respiratory issues. Vitamin E may be given to help reduce nail discoloration.
If you suspect you may have yellow nail syndrome, you should seek prompt medical advice.
Another common cause of yellow nails is staining from nail polish. Many brands of nail polish contain iron oxide which over time can absorb into the nail resulting in yellow toenails.
Repetitive painting of your nails can lead to discoloration. This is particularly common when using red, orange or darker shades of nail polish.
Frequent use of nail polish can also trap moisture under the nail bed which may lead to infection and therefore nail discoloration. You may notice yellow skin around your nails.
The simplest way to treat discolouration caused by nail polish is to leave the nails un-painted for a couple of weeks and they should return to their normal colour. When you do then want to repaint them, always apply a base coat and avoid reds and oranges, opting instead for lighter colours.
Applying a clear base coat before applying polish can help reduce staining and the risk of developing yellow toe nails.
Yellowing of the skin is the classic feature of jaundice but yellow toenails are often seen with it as well. Jaundice is a medical condition where a problem with the liver causes high levels of bilirubin, resulting in yellowing of the skin, eyes, mouth and nails.
It would be extremely unusual for the only symptom of jaundice to be yellow toenails, so if you have no other symptoms, you are unlikely to be suffering from jaundice. However, if you have noticed a yellow/green tinge to your skin or in the white your eyes, or have noticed your urine is darker or your faeces lighter than usual, you should consult your doctor.
Other possible, less common, causes of yellow toenails include:
Psoriasis is a chronic autoimmune disease causing patches of red, flaky skin covered with silver coloured scales. It is sometime associated with nail discolouration, typically yellow, brown or green and it may look like there is a drop of oil underneath the nail. Find out more about nail psoriasis and how to treat it.
This is a bacterial infection in the nail or surrounding skin that results in redness, inflammation and pus around the edge of the nail, and thickening and discoloration of the nails. It may affect the fingernails or toenails with the nails turning yellow over time.
Type 2 diabetes is often accompanied by poor circulation and nerve damage in the feet which can lead to yellowing or blackening of the toenails. Good foot care is vital for anyone suffering from diabetes, so if you have developed yellow toenails and are diabetic, consult your doctor promptly.
As we age, our nail structure changes and becomes more brittle, making them more prone to yellowing. It is therefore common for older people to have thick nails which often turn a yellowish colour.
Poor nail hygiene, such as not washing your hands regularly or failing to trim your nails, can lead to a buildup of dirt and bacteria, which can cause the nails to turn yellow.
Some medications, such as chemotherapy drugs, can cause yellowing of the nails as a side effect.
Nicotine and other chemicals in cigarettes can stain nails, leaving them yellowish. The occasional cigarette is unlikely to turn your nails yellow, but if you smoke regularly you may notice a gradually darkening tinge of yellow on your nails.
There are a few ways to treat yellow nails, such as trimming and filing your nails, using an anti-fungal cream or solution, and practicing good hygiene. Additionally, it is important to avoid further damaging your nails, as this can lead to further discoloration.
Yellow toenails may last anything from a few days to several months, depending on the underlying cause. For simple things such as nail varnish staining, it usually take s a couple of weeks for the nails to return to their normal color, but with fungal infections, yellow nails may take months to fully recover.
Treatment for nail fungus should be started as promptly as possible, so don’t ignore yellow toenails hoping they will just sort themselves out. Treatment for yellow nail fungus usually involves using one or more of the following:
Fungal nail infections are highly contagious so do keep those yellow toenails covered! If you think you may have an infection, it is highly recommended that you seek medical advice and treatment for your yellow nails.
There are many possible causes of yellow toenails, most of which aren't serious.
Thick, yellow toe nails are often caused by fungal nail infections which respond well to medication, or staining from prolonged nail varnish use.
Yellow nail syndrome is one of the more serious causes of yellow nails, usually associated with other problems such as breathing problems and lymphodema.
In many cases, yellow toenails also become thickened and may change shape. If this is the case, have a look at the thick toenails section to find out what is going on.
If you are also suffering from pain in your toes and none of these are sounding like your condition, visit the toe pain diagnosis section for help working out what may be wrong.
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Page Last Updated: 03/09/23
Next Review Due: 03/09/25