from: http://www.skinpatient.com/ptinfo/N/nails.htm

Nail care - the truth

All you needed to know but didn’t know where to ask 

NAIL POLISH

 Nail lacquer includes enamels, topcoats or base coats together or separately. The base coat is used to improve bonding of enamel to the nail. A topcoat improves the depth and luster of the enamel and helps to prevent chipping and abrasion.

Six groups of chemicals constitute nail polishes.

1. Cellulose film formers – (nitrocellulose) these add gloss to the nail.
2. Resins – toluene sulphonamide formaldehyde resin improves gloss and adhesion to nails
3. Plasticizer – dibutylpthalate gives flexibility and plasticizes the cellulose.
4. Thixo tropic suspending agents – bentonite. These keep pigments in suspension after shaking the polish.
5. Solvents – Butyl and diluents (toluene) keep nitrocellulose, resin and plasticizer in a liquid state and control the application and drying time.
6. Color substances. These could be inorganic or organic colors.

“Pearls” or “frosts” are due to bismuth oxychloride and titanium dioxide coated with mica and guanine.

Reactions due to nail polish

 These appear commonly on any part of the body that can be reached by nails. Interestingly the skin around the nails are not affected. The eyelids are the first affected along with face, neck and chest. Nail polish eczema can be seen on partners and close contacts as well. Toluene sulphonamide formaldehyde resin is the most common culprit. Sometimes nickel pellets are used in nail polish and can cause reactions in people who have allergic reactions to nickel. 

Nail plates can be stained due to use of nail polish. This starts near the cuticle ( the base of the nail ) and slowly moves forward.

 Nail polish removers

 Acetone is a solvent and is used for this purpose. It can cause drying of nail plate and cause soreness of the nail folds.

 Thinning and splitting of nail can occur.

 “Ready made” nails

 Plastic nails are available in various sizes and shapes. These are cut and trimmed and stuck to the nail with a strong adhesive. They should be removed within 3 days. They may cause onycholysis ( destruction of nails ). As ever contact allergy to the ingredients can occur.

 Nail “Hardness” 

Nail can be hardened by substances such as formaldehyde preparations. These can result in bleaching under the nail and bluish discoloration of the nails.

 “Stick-on” nail polish

 A small colored synthetic film with an adhesive is used which sticks to the nail. Adverse effects include flaking, roughness, broken nails, disappearance of cuticle.

 Nail wrapping

 This is used if the free edge of the nails is repeatedly splintered. The free edge of the nails is cemented with cotton wool, paper or plastic film and is fixed with nitro cellulose glues. The procedure needs to be repeated every 2 weeks.

 Cuticle removers

 These contain sodium potassium hydroxide or quaternary ammonium urea. The manufacturers instruction should be strictly followed otherwise irritation can occur.

Nail cream

This is water in oil moisturizing cream with low water and high lipid content. It can be used to prevent brittleness.

 Nail buffing

 This is done to remove small particles of nail debris to increase the luster and smoothness of plate. Buffing creams contain waxes and finely ground pumice and must be over used on thin nails.