Toenail discoloration is a common issue. Possible causes of discolored toenails range from minor toe injuries and fungal infections to more severe health conditions, such as melanoma.
Toenails are usually semi-transparent but can turn purple, black, green, or yellow, depending on the cause.
Several health conditions and other factors can cause toenail discoloration. Some require no treatment, but others may signal a serious condition that needs treatment from a doctor.
This article lists six potential causes of toenail discoloration, including their treatment options and when to get help from a doctor.
Nail fungus is a
Nail fungus affects toenails more often than fingernails, with the infection typically developing on the big toe first.
Toenail fungus can begin as a skin infection called athlete’s foot. It can also occur when other yeasts or molds get into the nail through cracks or breaks in the skin or nail.
The review suggests that nail fungus affects around 5.5% of people globally. Toenail fungal infections may be more likely to affect:
- older people — the prevalence is 0.4% in children in North America and up to 35% in adults over 65 years
- males
- those who walk barefoot in shared bathrooms or locker rooms
- people with fungal infections elsewhere on the body
- individuals wearing tight shoes
- people with certain health conditions, including:
- people who smoke
Treatment
It can be challenging to treat nail fungus, and relapses are common. Oral antifungal medications are the main treatment for nail fungal infections, although some people may experience adverse side effects.
Other potential treatment options include:
- topical antifungal medications
- lasers
- photodynamic therapy
- scraping away, trimming, or fully removing the affected tissue
Psoriasis is a chronic condition that causes the body to make skin cells more quickly than they break down. This process causes a patchy buildup on the skin.
A 2021 review estimates that 40% to 50% of people with psoriasis have nail symptoms. Psoriasis may cause the nails to:
- change color
- get thicker
- lift off the nail bed
- crumble
- develop dents
Treatment
Treatments for discolored nails in people with nail psoriasis
- topical applications that a person applies directly to the nails
- systemic medications
- phototherapy
Injuries can cause toenail discoloration due to a subungual hematoma, which involves blood and fluid collecting under the nail. A red area will appear that may turn purple over time and then brown or black.
People may notice this after they stub their toes, wear tight shoes when running, or do anything else that causes small blood vessels to break and leak blood under the toenail.
Treatment
Toe injuries can often heal with home treatments, such as over-the-counter pain relief and rest, ice, compression, and elevation (RICE).
The body will usually absorb the pooled blood over time, and a healthy new toenail will grow out.
Subungual melanoma is a severe form of skin cancer that can appear as a dark stripe running lengthwise down the toenail. This stripe may have uneven edges and be wider than
Melanoma affecting the nail is rare but may be more likely to affect the following people:
- African American, Asian, and Hispanic people
- males in their 60s
- females in their 50s
- those with a family history of melanoma
Treatment
Treatment for subungual melanoma
Doctors will not usually use radiation to treat melanoma of the nail, but it may be necessary in some cases. If cancer has spread beyond the nail, people may also need immunotherapy.
Yellow nail syndrome can cause yellow toenails, breathing problems, and swelling in the legs.
This is a very rare condition that typically affects older adults. Researchers do not know for sure what causes yellow nail syndrome, although it sometimes runs in families.
Treatment
Treatments for yellow nail syndrome
To address the nail discoloration, doctors may recommend oral vitamin E or antifungals. In some people, the yellow nails will resolve on their own.
Nail polish can also cause toenail discoloration if the polish penetrates deep into the keratin layers in the nail. The discolored nail eventually grows out, although it can take time.
Treatment
If someone’s nail discoloration is due to staining from cosmetics, a doctor may recommend avoiding the cosmetics. However, the staining may not necessarily be harmful and may only require treatment if someone dislikes the appearance.
Toenail discoloration may cause the nail to turn one of several different colors, including:
- white
- yellow
- brown
- green and black
- dark red and black
Other symptoms that may occur with toenail discoloration include:
- thickening nails
- nails that crack easily
- nails lifting off the skin
- pitting, which is the formation of little dents in the nail
- blood under the nails
- a buildup of debris under the nails
The specific symptoms someone has may depend on the underlying cause.
Toenail color changes do not necessarily mean that someone has a serious condition. However, it could indicate that a doctor’s appointment is necessary.
Toenail discoloration may improve without treatment if the toe has had a chance to heal from an injury. Alternatively, if cosmetics are staining the nail, the discoloration may improve when someone stops using the cosmetics.
It is a good idea to speak with a doctor for evaluation and treatment if someone has:
- a dark stripe running the length of the toenail appears or changes
- nail pain
- swelling or signs of infection
- pitted nails
- bleeding around the affected nail
Toenail discoloration is a common problem with many possible causes, ranging from injuries and staining to severe health conditions, such as melanoma.
Nail fungus is the most frequent cause of discolored toenails, and doctors may be able to treat it with antifungal medication.
Aside from injuries, most conditions that cause toenails to change color may require treatment from a doctor.