Q: I have a client who opted for natural nails after having an allergic reaction to acrylics. I started her on a product specifically made for the transition from acrylic to natural nails that has formaldehyde in it. She did great for about six months, then every nail started peeling. I wonder if she could be having an allergic reaction to formaldehyde. I’ve been researching the subject but can find very little information on it. Do you think that’s the problem?

A: Dr. Pheobe Rich: First, with regard to your client’s allergic reaction to acrylics, there are four main nail cosmetic ingredients that have the potential to cause allergic reactions: free formaldehyde, acrylates, toluene sulfonamide formaldehyde resin (TSFR), and rarely, cyanoacrylate glue. In each case the patient is sensitized by exposure to the ingredient over a period of time. Once they become allergic, they will have a reaction every time they are exposed to the ingredient. It is possible that your client who is allergic to acrylates could use a different system such as silk wraps or gels.

The formaldehyde in the transitional product you are using could be dehydrating the natural nail and causing the nail plate to peel. Nail polish remover can cause similar changes when over-used. Your client may have become sensitized to the new product. It is important to distinguish between TSFR and free formaldehyde. They are not the same. Formaldehyde has been banned by the FDA in concentration greater than 5% but can be found in lower concentrations in some nail hardeners. TSFR is a resin that is also a sensitizer and is found in many nail polishes.

Q: For a long time I heard that the only real cure for a true fungal infection is oral medications that must be taken for six months. Recently you recommended a topical product in this column. Are topicals really effective?

Editor’s note: It’s understandable that you’re confused. Several years ago the FDA established a policy disallowing claims about the efficacy of topical antifungals on hair and nails. Since fungal infections are rooted under the nail plate, it is difficult for topical medications to penetrate. In recent years, however, several of our panel doctors have reported using topical treatments with good results.

Dr. Phoebe Rich: There are several different types of fungal infections of the nail (also calledonychomycosis) and most of these are best treated with oral antifungal medications. The most common toenail fungus is called distal subungual onychomycosis and because the infection is deep in the nail bed, a topical medication will not cure it. Several superficial fungal infections (white superficial onychomycosis and even onycholysis where a yeast has invaded the nail bed) can be treated with a topical antifungal medication.

Topical medications come in many forms: creams, lotions, solutions, and even lacquer bases. These products can sometimes be very helpful in mild or superficial infections, but will not fully treat deep or severe nail fungal infections. Over the past decade several new safe and effective oral antifungal drugs have become available. These new medications allow most cases of nail fungus to be cleared. It is important for the nail technician to know that the spores of nail fungus can cause the infection to spread to herself and to other clients. Careful cleaning of instruments is essential to protect herself and other clients.

Dr.Roth: In the past, topical antifungal medications were essentially a waste of time. Over the years I have used them all with success ranging from approximately 10% to 30%. However, I have had an 80% success rate with a new topical product that contains a special ingredient, DMSO, that allows the medication to penetrate the nail. Since, even with oral medications, fungus will almost always eventually come back, I recommend my patients continue to use the product once or twice a week after the fungus appears to be gone.

Doctors generally recommend oral antifungals to treat deep or severe fungal infections of the nail, though at least one new topical solution shows promise for treating them successfully.

Q: Is there any way to treat or cure psoriasis of the nails?

A: Phoebe Rich: Psoriasis of the nails occurs in up to 50% of patients with psoriasis of the skin. It has several characteristic features, including pitting on the surface of the nail, onycholysis, nail bed thickening, and orange-brown discoloration in the nail bed. It is often confused with a fungal infection because the two conditions can look the same. A dermatologist can distinguish between the two conditions with laboratory tests.

The treatment of psoriasis of the nails is sometimes challenging. The simplest treatment is a topical lotion applied under the nail. For nail pitting which occurs in the nail matrix, topical medication does not easily penetrate to the matrix so injections of cortisone with a tiny needle are performed near the cuticle. This treatment works fairly well and is not as painful as it sounds because the skin is numbed first with a cooling spray. The shots are required every month until the nails grow out normally, which is usually 4-6 months. Often the nails will improve spontaneously as the skin psoriasis clears.