Brittle Nails
Brittle nail syndrome (BNS) is a common structural disorder of the nail plate in which the nail loses its flexibility and toughness and breaks easily. It affects about 20% of the population, with women affected twice as often as men, and can seriously impair appearance, fine hand function and quality of life.
From a structural and biochemical standpoint, the mechanical strength of the nail plate depends on three key factors: its water content (normally 18%–25%), its lipid and cholesterol sulfate content (which binds the layers of keratinized cells together), and a network of hard keratin fibers (K31–K40, K81–K86) rich in disulfide bonds.
Brittle nails develop in two main patterns:
- Horizontal layering (onychoschizia):
- Caused by breakdown of the cell junctions (desmosomes) and of the lipid layer that holds the keratinized cell layers together at the distal edge of the nail.
- Mostly driven by external factors: repeated wet–dry cycles (frequent soaking followed by air drying) and exposure to detergents or nail polish removers (acetone), which strip the nail of its natural moisture and protective lipid film.
- Longitudinal splitting (onychorrhexis):
- Caused by disordered or damaged cell division in the proximal nail matrix.
- Keratin production is interrupted in longitudinal bands, creating deep, weak ridges along which the nail easily tears lengthwise. This pattern is usually linked to internal factors, aging or chronic skin disease.
Main Causes
- External and environmental factors (most common):
- Chronic water exposure (laundry and cleaning work, health care workers who wash their hands often).
- Nail salon chemicals: acetone-based removers, formaldehyde-containing polishes and high-alcohol hand sanitizers.
- Repeated minor trauma: typing with the nail tips, scratching, and poor filing technique.
- Medical and hormonal factors:
- Thyroid disease: Hypothyroidism reduces sweating, dries out the skin and nails, and lowers blood flow to the nail matrix.
- Iron deficiency anemia: Less oxygen reaches the nail matrix, and the nails may eventually become spoon-shaped (koilonychia).
- Natural aging (senile brittle nails): Blood supply to the fingertips and lipid production both decline with age.
- Associated skin diseases: Nail lichen planus, nail psoriasis, alopecia areata and nail eczema.
- Nutritional deficiencies: Low biotin (vitamin B7), low protein or sulfur-containing amino acids (cysteine, methionine), and low zinc and calcium.
Brittle nails are often mistaken for mild nail fungus, and many patients apply antifungal products on their own, which only makes the nails drier and more brittle. At Haute-Derma, assessment of BNS begins with measuring nail hydration and dermoscopic examination to distinguish onychoschizia from onychorrhexis, together with screening of ferritin/serum iron and thyroid function (TSH, FT4). Our treatment plans focus on rebuilding the lipid–keratin barrier, combined with intensive occlusive moisturizing.
Clinical Features and Types
- Onychoschizia (distal layering): The nail plate splits into two or more horizontal layers at the free edge. The nail is thin and sheds fine flakes of keratin when rubbed.
- Onychorrhexis (longitudinal ridging and splitting): Prominent longitudinal ridges appear, along with deep splits running from the base of the nail to the free edge, so the nail tears lengthwise on impact.
- Reduced flexibility: The nail plate loses its elasticity and becomes either very hard yet easily shattered (hard brittle) or soft and easily bent (soft brittle).
Onychoschizia vs. Onychorrhexis: Key Differences
| Feature | Horizontal layering (onychoschizia) | Longitudinal splitting (onychorrhexis) |
|---|---|---|
| Direction of splitting | Parallel to the nail surface (horizontal layers at the free edge) | Perpendicular to the free edge (splits run along the length of the nail) |
| Where damage starts | Free edge and distal corners of the nail plate | Nail matrix and proximal nail fold, gradually spreading across the whole plate |
| Core mechanism | Loss of water and of the lipids binding the keratin layers of the nail plate | Disordered cell division and structural damage in the nail matrix |
| Main cause | External (frequent water exposure, acetone, minor trauma) | Internal (thyroid disease, iron deficiency, lichen planus, aging) |
| How it feels | Flaky, layered tip of the nail | Rough surface with longitudinal ridges and grooves |
| Recovery | Fast (improves well once chemicals are avoided and nails are moisturized) | Slower (the matrix needs 3–6 months to recover) |
Treatment and Rebuilding the Nail Plate
Managing brittle nail syndrome takes a combined strategy: preventing external damage, restoring lipids and moisture locally, and correcting nutritional deficiencies:
Protecting the Nails From External Damage
- Wear protective gloves: Always wear cotton-lined rubber gloves for contact with water and cleaning products, when washing dishes or gardening.
- Change your nail care habits:
- Stop using acetone-based removers completely and switch to an acetone-free remover containing oils.
- Take a break from gel polish and acrylic nails for at least 2–3 months.
- File correctly: use a glass nail file and file in one direction only, from the sides toward the center, never in a back-and-forth sawing motion.
Topical Repair of Lipids and Moisture
- Soak and smear technique:
- Soak the fingertips in warm water for about 5–10 minutes so the nail plate absorbs water.
- Immediately apply a rich moisturizer containing low-strength urea (5%–10%), 5% lactic acid, ceramides, cholesterol or petrolatum over the whole nail plate and nail folds.
- Wear thin cotton gloves overnight to boost absorption under occlusion.
- Medicated hydrating nail lacquer: Apply a medical-grade lacquer containing hydroxypropyl chitosan (HPCH), silicic acid (silicon) or sulfur once a day. HPCH binds to nail keratin, reduces water loss through the nail plate (TEWL) and helps restore the structure of cracked nails.
Systemic Supplementation
- Biotin (vitamin B7): 2.5–5 mg by mouth daily, continuously for 3–6 months. Biotin activates carboxylase enzymes involved in fatty acid synthesis and keratin bonding, and has been shown clinically to increase nail plate thickness by 25%.
- Iron and ferritin: If serum ferritin is below 30 ng/mL, give 60–100 mg of elemental iron daily together with vitamin C.
- Silicic acid with collagen peptides: Improves the mechanical strength and elasticity of the nail's keratin framework.
