Thyroid diseases such as hyperthyroidism or hypothyroidism may cause brittle nails or splitting of the nail bed from the nail plate (onycholysis).
Severe illness or surgery may cause horizontal depressions in the nails (Beau's lines).
Psoriasis may cause pitting, splitting of the nail plate from the nail bed, and chronic destruction of the nail plate (nail dystrophy).
Other conditions that can affect the appearance of the nails include systemic amyloidosis, malnutrition, vitamin deficiency, and lichen planus.
Skin cancers near the nail and fingertip can distort the nail. Subungal melanoma is a potentially deadly cancer that will normally appear as a dark streak down the length of the nail.
Darkening of the cuticle associated with a pigmented streak may a sign of an aggressive melanoma.
Arsenic poisoning may cause white lines and horizontal ridges.
Silver intake can cause a blue nail.
Certain antibiotics can cause lifting of the nail from the nail bed.
Chemotherapy medicines can affect nail growth.
Normal aging affects the growth and development of the nails.
Call your health care provider if
Call your health care provider if you have:
A new or widening dark streak in the nail
White color under the nails
If you have splinter hemorrhages, see the doctor immediately.
What to expect at your health care provider's office
The health care provider will look at your nails and ask questions about your symptoms. Questions may include:
What is the abnormality?
Are the nails an abnormal color?
What color are they?
Are there red lines running the length of the nail (splinter hemorrhage)?
Are they an abnormal shape?
Has the texture changed?
Has the thickness changed?
Are the nails pitted?
Are the nails detached?
Are there ridged nails?
Which direction does the ridging go?
Does the whole end of the finger look enlarged?
Is there a lack of luster?
Are the nails brittle?
Is it the hands?
Is it the feet?
Is it only on one side?
Are both sides the same?
Is it only one specific nail?
Have you had an injury to the nail?
Do you bite your nails?
Do you pick your nails or rub the fingers or toes chronically?
Are the nails frequently moist?
Do you use nail polish?
What other symptoms are also present?
Diagnostic tests will depend on what other symptoms, if any, exist. These may include x-rays, blood tests, or examination of parts of the nail in the laboratory.
Do not bite, pick, or tear at your nails (in severe cases, some people may need psychological help or encouragement to stop these behaviors).
Keep hangnails clipped.
Wear shoes that don't squeeze the toes together, and always cut the nails straight across along the top.
To prevent brittle nails, keep the nails short and avoid nail polish. Use an emollient (skin softening) cream after washing or bathing.
Using the vitamin biotin and clear nail polish that contains protein can help strengthen your nails.
Kevin Berman, MD, PhD, Atlanta Center for Dermatologic Disease, Atlanta, GA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.