Why are my nails yellow

Noticing that your fingernails or toenails have begun to develop a yellow tint can be both frustrating and concerning. While occasional staining from nail polish or smoking can temporarily alter nail colour, persistent yellowing often indicates an underlying health or lifestyle factor. Understanding the common causes of yellow nails helps you identify whether simple self‑care measures are sufficient or if professional evaluation is needed to address a potential medical issue.

Staining from external sources
Frequent use of dark nail polishes without a protective base coat allows pigments to seep into the nail plate, resulting in a yellow hue over time. Tobacco smoke contains tar and nicotine that can stain nails and fingertips. Treating stained nails involves removing polish regularly, applying a clear base coat before colour, and gently buffing the nail surface. For smokers, reducing or quitting tobacco use prevents further staining and promotes overall nail health.

Fungal nail infections
One of the most common medical causes of yellow nails is onychomycosis, a fungal infection of the nail plate and bed. The fungus thrives in warm, moist environments and often starts at the nail edge, spreading inward. Infected nails may become thickened, brittle, crumbly and develop a strong odour. Over‑the‑counter antifungal creams seldom penetrate the nail effectively; prescription oral antifungals or medicated nail lacquers prescribed by a GP or dermatologist are usually required. Early treatment prevents the infection from worsening and affecting multiple nails.

Age‑related nail changes
As people age, nails naturally grow more slowly and can develop ridges, thickness and colour changes, including yellowing. Reduced circulation and cumulative exposure to environmental factors contribute to these changes. Keeping nails trimmed, moisturising the cuticles and having regular checks with a healthcare professional if colour changes seem excessive helps maintain nail integrity in later life.

Psoriasis and other skin conditions
Skin diseases such as psoriasis can affect the nails, producing yellow‑brown pitting, thickening and separation of the nail plate from the nail bed. This condition, known as nail psoriasis, often occurs alongside skin symptoms such as red scaly patches. Managing psoriasis with topical or systemic treatments under dermatology guidance often improves both skin and nail appearance, reducing yellow discolouration and discomfort.

Smoking and lifestyle factors
In addition to staining, smoking impairs blood flow to the extremities, compromising nail growth and colour. Nutritional deficiencies—particularly of vitamins A, C, D and biotin—can lead to brittle, discoloured nails. A balanced diet rich in fruits, vegetables, lean proteins, whole grains and healthy fats supports nail health. Staying hydrated and avoiding excessive exposure to chemicals such as detergents or solvents also protects the nails’ natural appearance.

Medical conditions and systemic illness
Yellow nails can signal systemic issues. In the yellow nail syndrome, a rare disorder, nails thicken, slow their growth, and develop a yellow‑green colour, often accompanied by respiratory problems and lymphoedema. Chronic respiratory conditions such as bronchiectasis and sinusitis sometimes coexist with yellow nail changes. Diabetes and liver or kidney disease can also affect nail colour. If yellowing is accompanied by other symptoms—such as swelling of the limbs, respiratory issues, fatigue or changes in skin tone—you should seek medical evaluation promptly.

Medication side effects
Certain medications may alter nail colour as a side effect. Chemotherapy drugs, some antibiotics such as tetracyclines, and antimalarial drugs like chloroquine can cause yellowing or dark bands on the nails. If you start a new medication and notice nail discolouration, review the side effect information and discuss alternatives or supportive measures with your prescribing doctor rather than discontinuing treatment abruptly.

Environmental irritants and habit‑related trauma
Frequent exposure to water, detergents and harsh cleaning products weakens nails and washes away natural oils, leading to dryness, brittleness and discolouration. Repeated microtrauma—such as tapping nails on hard surfaces or aggressive manicuring—can damage the nail plate and cause yellowing. Wearing gloves during household chores, using a gentle soap, and avoiding aggressive filing or cuticle cutting preserves nail health and colour.

Home care and cosmetic remedies
To brighten yellowed nails at home, soak them for ten minutes in a mixture of warm water and a few drops of lemon juice or vinegar, which gently bleaches surface stains. Applying a whitening toothpaste and lightly brushing the nails can also remove mild staining. Always follow with thorough rinsing and moisturising. Over‑the‑counter nail brightening kits containing mild hydrogen peroxide formulations may help, but excessive use can weaken the nail plate.

When to seek professional advice
If nail yellowing persists despite removing stains, improving hygiene and treating minor causes, consult your GP or a dermatologist. They can examine your nails, review your medical history and, if necessary, perform laboratory tests or nail clippings to identify fungal infection or systemic disease. Early diagnosis of fungal infections or systemic conditions such as diabetes or thyroid disorders leads to more effective treatment and better nail outcomes.

Summary
Yellow nails often result from external staining, fungal infections, ageing, psoriasis, smoking, nutritional deficiencies, medication side effects or systemic disease. Addressing simple causes through protective base coats, gentle cleansing, moisturising and dietary support can restore normal nail appearance. Persistent or unexplained yellowing especially when accompanied by other symptoms requires professional evaluation to identify and treat any underlying health issues. With proper care and timely medical attention you can maintain healthy, clear nails.