Nail cosmetics are big business in the US. A specialist highlights some benefits of nail cosmetics and offers tips to protect your patients from potential dangers. By Phoebe Rich, MD 38 Practical Dermatology October 2007 omen and men today value healthy, well- nails, it also makes them brittle, which is not desirable. Therefore, groomed nails. The appearance of the nails patients should avoid formaldehyde-containing products. may reflect overall health and good hygiene. Benzophenone is another allergen commonly found in nail For women, adornment of the nails may cosmetics. Nickel beads used in nail lacquers have largely been reflect a desire to accessorize or cosmetically replaced with polyester beads that are non-allergenic, howev- enhance the appearance the nails, whimsy, and/or artistic expres- er, the metal is still sometimes used. sion. Salon-applied nail enhancements can even help to camou- The clinical presentation of a reaction can help determine flage surface irregularities, such as pitting, or dystrophic nails the source of the allergen, based on the chemistry of the mate- resulting from dermatologic diseases like psoriasis. The range of rial used. Allergic contact dermatitis to acrylics usually pres- Woptions for nail adornment is wide, ranging from the simple ents in a periungual distribution with a hyperkeratotic or even application of polishes and lacquers to the use of acrylic nail vesicular-type reaction. Patients complain of pain, itching, and extensions to application of screen prints, jewelry, and more. burning, usually immediately after the nail procedure. Because There’s no doubt the cosmetic nail industry is large and acrylics polymerize very quickly, there is little opportunity for growing. In 2005, Americans spent $6.84 billion on salon transfer of the chemical, and the reaction is limited to the area services alone. This figure does not include spending on nail adjacent to the application site. care products and cosmetics from other sources, such as phar- By contrast, nail lacquer or polish hardens via evaporation macies and other retailers. Across the US, there are nearly rather than polymerization. Although a degree of hardening 400,000 licensed nail technicians at 54,000 salons. By con- happens very rapidly, full hardening occurs slowly over time. trast, dermatologists number around 12,000. The offending chemicals can be spread elsewhere on the body, Although there has been some widespread attention paid to including the neck and face. Eyelid involvement is very com- the issue of salon hygiene, the reality is that nail salons and nail mon, often in a focal distribution, though it may be diffuse. enhancements are not necessarily inherently dangerous. Millions Polyester resins have replaced tosyl formaldehyde resin of women use nail cosmetics with no complications. resin in over-the-counter and most salon products, but it may Nonetheless, by nature of the sheer volume of patients who fre- be found in some products. Patch testing easily and effective- quent nail salons, dermatologists are likely to encounter patients ly identifies allergy to tosyl formaldehyde, and a simple use who have experienced a negative outcome associated with a nail test can be performed. salon service. The majority of these problems will be linked Much development in the nail cosmetics industry comes from either to the materials used or to the mechanical procedures per- advancements in the plastics industry, and new acrylates contin- formed at salons. As dermatologists, we must be prepared to ue to emerge. To efficiently screen for acrylate allergies, test with effectively identify and treat potential nail problems and educate ethyl methacrylate, which cross-reacts most other acrylates, obvi- patients so that they can safely pursue nail salon services. ating the need to individually patch test for each form. Methyl methacrylate is highly allergenic and has been banned by most states but may be used in products in some AllergicReactions reactions. to Allergic Materials reactions associated with nail cosmet- discount salons because it is rather inexpensive. It is more ics are nothing new. In fact, the industry continues its efforts to durable than ethyl methacrylate, which replaced it and is gen- minimize the use of some common allergens and irritants. erally considered safer. Acrylates, of which there are multiple types, can be allergenic. Irritant reactions. Water is a significant irritant, and soak- Formaldehyde resin is one of the most common allergens associ- ing of the nails during a manicure can be problematic. ated with nail cosmetics. Although it is no longer used in over- Reaction to nail polish remover is probably the most com- the-counter nail products, it can be found in some salon products. monly seen irritant contact reaction. Acetate has largely Formaldehyde can still be found in some nail cosmetics. replaced acetone as the primary ingredient in nail polish According to FDA regulations, formaldehyde may be present in removers, but it is only slightly less dehydrating. nail cosmetics and hardeners in concentrations below three per- Contact irritants can produce various clinical presenta- cent, and such products should not be intended to touch the skin. tions, the most common of which are paronychia, onycholy- However, these federal guidelines apply to products traded across sis, and brittle nails. state lines, so it is possible for an in-state manufacturer to produce Paronychia results from a cycle initiated by loss of the cuti- and locally distribute formulations that contain higher concentra- cle as a result of the irritant reaction. Absence of the cuticle tions of formaldehyde. This is the case in my home state of permits moisture, yeast, and bacteria to enter the nail fold, Oregon, where I have seen patients react to a local product that leading to inflammation and paronychia. Onycholysis may contains formaldehyde. Although formaldehyde hardens the result from irritation caused by water or nail polish remover. October 2007 Practical Dermatology 39 Nail Cosmetics Onychoschizia—peeling and brittleness at the nail tip—is most common in individuals who frequently remove nail pol- ish. Some women change polish several times weekly to match outfits or simply on a whim. However, we recommend that patients remove polish only one time weekly. Note that nail yel- lowness among women who fre- quently paint their nails likely results from staining or discol- oration produced by nail enam- el dyes. Keratin granulations may also occur in patients who remove nail polish frequently as well as in individuals who leave pedicures in place for prolonged periods of time (three months is common). Allergic contact dermatitis (top, left). Atypical mycobacterium as seen in patients after pedicures given in con- These granulations are not fungal taminated water (top, right). Brittle nails/onychoschizia (bottom, left). Keratin granulomas (bottom, right) . and are thought to be produced by the base coat, though this is not proven. avulsion, you will feel some give when you hit the matrix. When pressure is applied to long artificial nails, which are harder than natural nails, the nail will not bend or fracture. Instead, the nail MNailany Traumacases of nail trauma result from procedures performed will act as a lever and pull away from that loosely adhered nail in the nail salon. Mechanical problems may result in onychol- matrix. A natural nail, by contrast, is much more flexible, and ysis and paronychia. The most common cause of trauma is use would quickly bend or fracture under pressure. of sharp instruments, such as clippers, metal cuticle pushers, Mechanical problems can lead to infection, bacterial, fungal and electric drills. Electric dremel drills are used to file thick (primarily dermatophyte and yeast), or viral. Infections can be acrylic nails and to shape or file natural and artificial nails. If spread from client-to-client in the salon when tools are not sani- the drill slips, it can cause damage to the nail and/or trauma tized. A case of fatal MRSA following a pedicure has been docu- and cuts to the skin that may lead to infection. Furthermore, mented. This specific case involved a paraplegic woman. The gen- the drill tips may not be sanitized or changed regularly and eral recommendation is that paraplegics and diabetics avoid pedi- may be used from client-to-client, introducing the possible cures, since they may not detect cuts and nicks that may lead to spread of infection. Home drill kits are also available. While serious infection. Such extreme cases are thankfully rare, but these personal use devices limit the threat of infection spread, infections can occur with some frequency. their use can cause damage in and around the nail unit. When patients present with paronychia, attempt to culture Clipping of the cuticles or manipulation with sharp metal pus from the area in order to make a specific bacterial diagno- cuticle pushers can damage the cuticle, decreasing defense sis and institute appropriate antibiotic therapy. Dark nails against infection. A poorly sanitized clipper may even intro- associated with onycholysis are usually associated with duce infection. We advise patients to never clip their cuticles. pseudomonas, though there may be other causes. Long natural or artificial nails can act as a lever that lifts the There is potential viral spread by incompletely sterilized pedi- nail plate whenever pressure is applied to the nail tip. cure implements. Paring of a wart that is misdiagnosed by the Constant use of the hands—typing, opening cabinets, etc.— patient or salon technician as a callous, for example, can lead to produces chronic minor trauma that can lead to onycholysis viral spread for the individual and among clients. Herpetic whit- and splinter hemorrhages among other issues. low may be associated with nail services. The nail plate naturally is attached tightly to the nail bed but Pedicure procedures may present a unique opportunity for loosely over the matrix. For this reason, when performing a nail infection.