Onychomycosis is caused most commonly by Trichophyton rubrum or T. mentagrophytes. About 10% of all persons worldwide and 40% of those ≥60 years old are believed to have the disease. Risk factors include older age, diabetes, poor peripheral circulation, smoking, HIV infection, psoriasis, and immunosuppression. Left untreated, onychomycosis can cause nail plate destruction, ingrown nails, and (particularly in patients with diabetes) secondary infections. Guidelines on treatment of onychomycosis have been published.

In recent years, the availability of new types of lasers has improved the treatment of disfiguring cutaneous vascular abnormalities. Vascular lesions of the skin that can be treated with lasers include port-wine stains, telangiectases, and strawberry hemangiomas (RA Silverman, Pediatr Clin North Am, 38:811, Aug 1991).

Tretinoin (tret' i noyn; all-trans-retinoic acid; Retin-A), a derivative of vitamin A, has been used for years for topical treatment of acne. More recently, it has also been used to improve the appearance of skin damaged by chronic exposure to the sun, although not approved for this indication by the US Food and Drug Administration.

Topical tretinoin (all-trans-retinoic acid) has been used for years to treat skin damaged by chronic exposure to the sun (Medical Letter, 34:28, 1992). First approved by the FDA only for treatment of acne in concentrations ranging from 0.025% to 0.1% (Retin-A, and others), it has now been approved as an 0.05% formulation in an emollient cream base (Renova) for topical treatment of photodamaged skin. In recent years, alpha-hydroxy acids incorporated in some cosmetics have also been promoted as effective in improving the appearance of aging skin.

A long-pulse ruby laser (EpiLaser), has been cleared by the FDA for use in "permanent hair reduction."

Terbinafine (Lamisil - Sandoz), an allylamine synthetic antifungal, previously available in the USA in a topical formulation (Medical Letter, 35:76, 1993) has now been marketed for oral use in the treatment of fungal nail infections caused by dermatophytes. Oral terbinafine has been available in Europe since 1992.

Lasers have been used in dermatology for many years. Recently, however, improvements in laser technology have led to much wider use of lasers for treatment of cosmetic skin problems. Many different types of lasers are available; the US Food and Drug Administration gives manufacturers permission to market laser systems for specific indications.

Rosacea is a common, chronic inflammatory facial eruption of unknown cause. It is more prevalent in women than in men, and disease onset typically occurs after age 30. Rosacea is characterized by erythema, telangiectasia, and flushing, and sometimes by recurrent, progressive crops of acneiform papules and pustules, usually on the central part of the face. Some patients develop granulomas and tissue hypertrophy, which may lead to rhinophyma (a bulbous nose), particularly in men. Blepharitis and conjunctivitis are common. Keratitis and corneal scarring occur rarely.

Botulinum toxin type A has been marketed in the USA since 1989 for treatment of strabismus and blepharospasm and has also been used to treat cervical dystonia and some other muscular disorders.

Ecamsule (terephthalylidene dicamphor sulfonic acid), the first new sunscreen agent to be approved by the FDA in 18 years, is now available in the US in a moisturizer called Anthelios SX. Ecamsule has been used in Canada and Europe for more than 10 years.