These are the first symptoms of a…

Common Causes of Vertical Nail Splitting
1. Aging
The most common cause of longitudinal nail splitting is natural aging.

As we get older:

Nails lose moisture.
Keratin becomes more fragile.
Nails become thinner.
Longitudinal ridges become more visible.
These changes increase the likelihood of splitting.

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2. Repeated Trauma
Everyday activities can weaken the nail over time. BiologicalSciences

Examples include:

Frequent typing
Gardening
Manual labor
Nail biting
Picking at nails
Using nails as tools
Repeated injury may eventually produce a permanent split.

3. Excessive Water Exposure
Constant wetting and drying weakens the nail structure.

People at increased risk include:

Hairdressers
Healthcare workers
Cleaners
Dishwashers
Food service workers
Repeated exposure removes natural oils that keep nails flexible.

4. Harsh Chemicals
Frequent contact with:

Detergents
Cleaning products
Solvents
Nail polish removers containing acetone
can dry the nail and increase brittleness.

5. Iron Deficiency
Iron deficiency is a recognized cause of brittle nails.

Other symptoms may include:

Fatigue
Pale skin
Shortness of breath
Hair loss
Blood tests can confirm iron deficiency. HealthConditions

6. Vitamin Deficiencies
Healthy nails require adequate nutrition.

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Deficiencies associated with brittle or splitting nails include:

Biotin (rare)
Vitamin B12
Folate
Vitamin D (indirectly through overall health)
Zinc
Supplements should only be taken if a deficiency is confirmed, as excessive intake can be harmful.

7. Thyroid Disorders
Both hypothyroidism and hyperthyroidism may affect nail growth.

Possible symptoms include:

Brittle nails
Dry skin
Hair thinning
Fatigue
Weight changes
Sensitivity to temperature
8. Skin Disorders
Certain chronic skin diseases affect nail formation.

Examples include:

Psoriasis
May cause:

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infection
Nail pitting
Thickening
Splitting
Discoloration
Eczema
Chronic inflammation around the nails may weaken them. BiologicalSciences

Lichen Planus
Can produce thinning and longitudinal splitting.

9. Fungal Nail Infection
Although fungal infections more commonly affect toenails, fingernails can also become infected.

Signs include:

Thickening
Yellow discoloration
Crumbling edges
Distorted nail shape
A fungal infection is less likely when a single, clean vertical split is the only finding.

10. Rare Tumors of the Nail Matrix
Persistent splitting affecting only one nail—especially if it continues to worsen—may rarely be caused by a growth beneath the nail, such as:

Digital mucous cyst
Benign nail matrix tumor
Subungual melanoma (rare but serious)
Any persistent change affecting one nail should be evaluated by a healthcare professional.