Glossary
Ablation - partial removal of the nail plate.
Amorolfine - Topical nail lacquer applied once or twice a week for the treatment of dermatophyte or candidal nail infection. Over-the-counter medication available without a prescription. Not available from pharmacies in the United States.
Antifungals - Medicines that can kill or inhibit the growth of fungi.
Athlete's foot - A fungal infection of the feet, usually starting in the toes. Also called tinea pedis, this infection is commonly passed between persons sharing a common shower area.
Candida - A genus of fungus that can cause infection in several places in the body. Yeast infections are usually caused by a Candida species. Candida can cause a particular form of onychomycosis.
Candidal onychomycosis - A fungal infection of the nails caused by Candida albicans and includes three subtypes: Candida paronychia, Candida onycholysis, and Candida granuloma. Candidal onychomycosis is the only fungal nail infection that is more common in women than men. It also occurs in the immunocompromised rather than in those with intact immune systems.
Ciclopirox - Topical drug that inhibits or kills fungal cells. More effective at treating onychomycosis when combined with a newer oral onychomycosis medication. Placed directly on the affected nail each day until symptoms resolve. Marketed under the brand name Penlac.
Corneocytes - These are dead cells in the stratum corneum, which is the outermost layer of the epidermis. Corneocytes are filled with keratin.
Cuticle - The tissue that overlaps the plate and rims the base of the nail.
Debridement - The medical removal of all or a portion of the damaged nail plate to improve the healing potential of the nail.
Dermatophyte - A common label for a group of three different types of fungus that commonly causes skin disease in animals and humans. These anamorphic (asexual or imperfect fungi) genera are: Microsporum, Epidermophyton and Trichophyton.
Dermatophytids - An allergic reaction that occurs at a site other than the original fungal infection. The distant lesions are vesicles, or fluid-filled bumps, that can unite to form larger blisters. These skin lesions can be extremely uncomfortable or painful. Dermatophytids completely lack fungus.
Distal subungual onychomycosis - The most common onychomycosis. Affects the fingernails and toenails at the tip. The infection is most often caused by Trichophyton rubrum. The infection grows underneath the nail mostly and causes streaks and pits, which can deform the nail.
Epidermis - The outer layer of the skin.
Ergosterol - An essential component of fungal cell membranes.
Hyperkeratosis - An abnormal thickening of the stratum corneum or outermost layer of the epidermis.
Hyponychium - The thickened layer of epidermis beneath the free end of the nail plate.
Itraconazole - Antifungal drug that slows the growth of dermatophytes and may also treat candidal onychomycosis. This drug is given orally for up to twelve weeks. Marketed under the brand name Sporanox.
Keratin - A tough fibrous protein that is the primary component of nails, hair and skin. Keratin is essential for dermatophytes' survival, which is why dermatophyte infections occur in those areas.
Keratinolysis - dissolution or digestion of keratin.
KOH test - A test to quickly diagnose fungal infections of the hair, skin, or nails. A sample of the infected area is analyzed under a microscope following the addition of a few drops of potassium hydroxide (whose chemical formula is KOH) to dissolve skin cells, hair, and debris, leaving the fungi.
Leukonychia -a condition where white areas appear on the nail. The most common cause is injury to the nail matrix, but it can be caused by several disease processes, including onychomycosis.
Lunula - The half moon shaped white area at the base of the nail.
Nail bed - The tissue that is below the nail plate. It is the area on which the nail rests.
Nail biopsy -
Nail fold - The fold of skin around the base and sides of the nail plate.
Nail matrix - The living cells of the nail that produce the nail plate.
Nail plate - The hard sheet, primarily consisting of compressed keratin, that is commonly thought of as the fingernail or toenail.
Onycholysis - A loosening of the fingernail or toenail though usually incomplete, so that it still remains attached.
Onychomadesis - Complete loss of the nail, usually to a disease that affects the entire body rather than a local infection. Severe onychomycosis can lead to onychomadesis.
Onychomycosis - A fungal infection that affects the fingernails or toenails.
Paronychia - Infection of the nail fold surrounding the nail plate which often produces swelling and redness. It may be caused by a bacterial or fungal infection.
Proximal subungual onychomycosis - An uncommon form of onychomycosis in which the fungus infects the proximal nail fold through the cuticle and grows under and along with the nail. This type of onychomycosis usually only occurs in a patient that is immunocompromised in some way, such as by HIV infection, cancer, or chemotherapy.
Tea tree oil - An herbal preparation with antifungal activity against dermatophytes and candida. Also known as Melaleuca alternifolia. Better able to treat fungal skin infections rather than fungal infections affecting the nails.
Terbinafine - Marketed under the brand name Lamisil, this is a newer onychomycosis drug with activity against dermatophytes. It does not treat candidal onychomycosis. This drug is given orally over a period of four to twelve weeks.
Tinea - The name given to a fungal infection on the surface of the body. The name is combined with an anatomical location to describe the specific infection. Examples include Tinea corporis (fungal infection of the body; also known as ringworm); Tinea cruris (fungal infection of the genital area; also known as "jock itch"); and Tinea pedis (fungal infection of the feet, usually starting in the toes; also known as athlete's foot ).
Tinea unguium - Fungal infection of the fingernails or toenails, a subset of onychomycosis.
Topical treatment - A treatment that is applied on the infected nail or skin, and not administered orally or by any other route into the body. Topical treatments may absorb to a small degree through the skin, but they are usually intended to stay on the surface of the body.
Trichophyton rubrum - A dermatophyte that is the most common cause of onychomycosis. It also causes athlete's foot (tinea pedis) and jock itch (tinea cruris) among other tinea infections.
White superficial onychomycosis - A form of onychomycosis that stays near the top surface of the fingernail or toenail rather than growing under the nail. The infection forms a white, crumbly crust.