Yellow toenails can be caused by a variety of factors, including:
- Fungal infections (onychomycosis): This is the most common cause. Fungi thrive in warm, moist environments like inside shoes, leading to thick, yellow, brittle, or crumbly nails. The infection may cause discoloration, thickening, and sometimes pain or difficulty walking
- Aging: As people age, nails naturally change in color, thickness, and shape, often becoming more yellow without indicating disease
- Nail polish staining: Frequent use of nail polish, especially red, orange, or yellow shades, can stain nails yellow. This discoloration usually fades after stopping polish use
- Underlying medical conditions: Diseases such as diabetes, psoriasis, thyroid problems, tuberculosis, bronchiectasis, and jaundice can cause yellow nails. Yellow Nail Syndrome, a rare condition linked to respiratory issues and lymphedema, also causes yellow, thickened nails with slow growth and cuticle loss
- Other causes: Trauma to the nail, vitamin deficiencies (like vitamin E), and immune system issues can contribute to yellowing nails
In summary, yellow toenails are most commonly due to fungal infection or staining from nail polish but can also signal aging or serious health conditions requiring medical attention
