Susan Lee did not even know she had a fungal infection until the fourth toenail on her left foot fell off.

She first noticed white patches on her toenails a year ago. However, it wasn't until she went for a pedicure and her manicurist pointed out that her nails were splintering that she had an inkling something may be wrong.

'I thought it was just normal chipping because it didn't hurt at all,' said the 25-year-old secretary.

The white spots turned black but still, she ignored them and covered the spots with nail polish instead.

Then the worst happened.

'I noticed my nail had chipped and was about to peel it away when the whole nail fell off,' she recalled.

This finally prompted her to visit a pharmacy, where she was recommended an anti-fungal treatment.

While Lee did not see a doctor, a growing number of people are visiting dermatologists for nail problems.

According to the National Skin Centre (NSC), about 300 new cases of nail fungal infection are seen every year.

Dr Seow Chew Swee, a senior consultant dermatologist at NSC and head of the University Dermatology Clinic at the National University Hospital (NUH), said reasons for the increase include rising affluence and growing awareness of nail problems.

About 5 to 10 per cent of patients seen at NSC and NUH are there for nail treatments, most of whom are young working females who are 'concerned about their looks', he said.

Toenail problems make up about 80 per cent of the cases seen.

One reason more women face such problems is that they tend to wear heels and tight-fitting shoes, which subject their toes to much pressure, leading to nail deformities.

The four dermatologists Urban spoke to said nail problems can be symptomatic of life-threatening illnesses and should never be taken lightly.

Dr Eileen Tan of Eileen Tan Skin, Laser and Hair Transplant Clinic in Mount Elizabeth Medical Centre cited nail discolouration as a possible sign of trouble. 'I would advise someone to see a doctor when there is black or brown nail discolouration to rule out skin cancers,' she says.

Besides fungal infections, other common nail problems include brittle nails, nail ridges, ingrown nails and nail discolouration.

Urban gets three doctors - Dr Tan, Dr Joyce Lim, consultant dermatologist at Joyce Lim Skin and Laser Clinic in Paragon Medical Suites, and Dr Joyce Lee, consultant dermatologist at the NSC - to identify the symptoms and causes of five common nail problems and recommend treatments for them.

1. Brittle nails

Symptoms: Nails are weak and prone to breaking and layers of nails may flake off.

Causes: Poor nutrition, such as protein deficiency; frequent use of nail polish remover which can cause nails to become dry and brittle.

Treatment: Increase your protein intake if it is a nutrition deficiency. Protein-rich foods include milk, eggs and cheese.

Use a non-acetone nail polish remover, which is less drying. You can also combat brittle nails by applying a nail cream.

Try Sally Hansen's Get Strong Multi-Vitamin Nail Strengthener, $16.50, or its Complete Care 4-in-1 Treatment, $25.50, available from most Watsons and Guardian stores.

2. Nail ridges

Symptoms: Horizontal or vertical grooves that run from side to side of the nails.

Causes: Horizontal ridges, called Beau's lines after the French doctor who first diagnosed them, are caused by illnesses such as high fever and diabetes or by malnutrition.

Vertical ridges have no identified cause, but can result from trauma to the nails, such as wearing shoes that are too tight.

Treatment: It is more important to treat the underlying ailments that cause these ridges. When you are in good health, your nails will be smooth.

If the ridges bother you, they can be buffed away with an instrument such as the 4-Step Buffer, $10, from Sephora, B1-05 Takashimaya Shopping Centre.

3. Ingrown nails

Symptoms: Occurs when a sharp corner of the toenail digs into the skin at the side of the nail. There might be pain and mild swelling of the toe.

Causes: Trauma to the nail or tight-fitting shoes, which may cause toes to be squeezed together and pressure nails to grow sideways. Improper trimming of the sides of the nails may also cause the nails to grow abnormally.

Treatment: Stop wearing heels or tight shoes until the condition clears up.

In mild cases, use an antiseptic cream to calm the swelling and trim the side of the nails carefully. Try Dettol's Antiseptic Cream, $3.70, from Watsons.

For those with recurrent ingrown nails, it is best to go for surgery where part of the nail is removed and the nail cells killed using chemicals or laser so they do not grow back. An operation starts from $150, excluding consultation fees.

4. Discoloured nails

Symptoms: Nails that turn white, yellow, brown or black may be indicative of a more serious illness such as cancer.

Causes: White or pale nails may be due to anaemia, renal or liver diseases; yellow nails may be caused by severe lung or kidney diseases; and black or brown discolourations could be due to skin cancers such as melanoma or blood clots caused by nail injury.

Treatment: Do consult a doctor if your nails change colour for no apparent reason.

Use a base coat before applying nail polish to prevent the colour from staining your nails. If nails are already stained, try a treatment such as Scholl's 3-In-1 Discoloured Toe Nail Treatment, $15.50, from most Watsons and Guardian stores.

5. Fungal infection

Symptoms: Starts out with white, yellow or brown nails, with a thickening or distorted shape. The nails may become scaly and brittle, with white or black spots appearing. If left untreated, the entire nail may fall off.

Causes: Fungal nail infections occur when fungi attack the nails from an external source such as a public swimming pool or shower stall, or from the surrounding skin such as the toe webs or soles of the feet.

As fungi thrive in a warm, moist environment, this is more common in people who wear tight, closed-toe shoes over long periods of time.

Treatment: In less severe cases, treat the problem with a product containing anti-fungal compounds, such as Loceryl, $60, from most Watsons and Guardian stores.

In more serious cases, doctors may prescribe oral medication.

If the affected nails are deformed, they may have to be surgically removed to allow anti-fungal creams to penetrate the nail bed, the source of infection.

An operation starts from $150.

This article was first published in Urban, The Straits Times on Jan 2, 2009.