Flashcards in J-overview Deck (38):
What is Onychomycosis? (also known as Tinea Unguium)
Fungal Disease that can affect one or more of the anatomical components of the toenails or fingernails.
Fungal Pathogens that invade and break down the normal keratin of the skin, hair and nails.
Three fungal species of Onychomycosis
Dermatophytes, Yeasts, and Nondermatophyte molds
Two most common Dermatophytes
T. rubrum and T. Mentagrophytes
Characterized by thickening, scaling, and discoloration of the nail and nail bed.
Family of durable protein polymers that are found in epethelial cells. They provide structure strength to skin, nails, and hair.
the fungus that causes onychomycosis in the majority of cases caused by yeast
most frequently seen among elderly and the immuncompromised. Most common is Scopulariopsis, Acremonium and Fusarium.
Thickened layer of the epidermis beneath the free end of the nail
made up of the proximal nail fold (PNF), the nail matrix, the nail bed, and the hyponychium.
crescent shaped area visible at the base of the fingernails, active area of nail bed growth
Horny structure from which the nail develops
Nail Plate Growth
Toenail growth is slower than fingernail growth.
-fingernails grow appox 1/8inch per month - 6mths for complete
-toenail grow aprox 1/16 inch per month-* 12-18 months for complete
Types of Onychomycosis
-Distal Lateral Subungual onychomycosis
-White superficial onychomycosis
-Proximal subungual onychomycosis
Distal Lateral Subungual Onychomycosis(DSLO)
most common type of onychomycosis. Most often caused by T. rubrum/t. mentagrophytes. Starts as infection of hyponychium and distal or lateral nail bed. Moves subungually under the nail plate from the distal/lateral nail bed into the proximal nail bed and finally upward into the nail plate.
Signs and Symptoms of DSLO
-distal/lateral loosening of the nail from the nail bed
-hyperkeratosis(thickening and over growth.
may also progress to total dystrophic onychomycosis
overgrowth of the horny layer of the epidermis(thickening of nail and overgrowth)
Total Dystrophic Onychomycosis
Condition characterized by total destruction of the nail plate
White Superficial Onychomycosis (WSO)
less common type of onychomycosis than DLSO. Pathogens invades through the nail plate, then moves into the nail bed and hyponychium. Most frequently caused by T. mentagrophytes.
Signs and Symptoms of White Superficial Onychomycosis
-white dots or tiny punctures speckled across the surface of the nail, which gradually spread to involve the entire nail. Nail plate becomes white and crumbles as infection spreads.
Proximal Subungual Onychomycosis
Rarely seen, caused primarily by T.rubrum. Invades the nail unit through the stratum corneum of the proximal nail fold. Seen frequently in patients with AIDS. May be presenting signs of AIDS.
Signs and Symptoms of Proximal Subungual Onychomycosis
-white discoloration under the nail plate in the area of the lunula, with the nail plate remaining intact and the distal end of the nail unit appearing normal.
Rare condition that may occur only in individuals with a chronic Candida infection of the skin and mucous membranes. Most common pathogen is Candida Albicans.
Signs and Symptoms of Candidal Onychomycosis
-Thickening of the nail bed
-yellow-brown discoloration of the nail plate
-swelling of the proximal and lateral nail folds that result in a "drumstick" appearance of the digits.
Less than 25% of nail affected by disease
26% to 74% of nail affected by disease
More than 75% of nail affected by disease
Diagnosis of Onychomycosis
-Primary Criteria is white/yellow or orange/brown
patches or streaks
-Secondary is Onycholysis, Subungual
hyperkeratosis/debris, and Nail plate thickening
-Positive microscopic evidence
-Positive Culture of dermatophyte
loosening or detachment of the nail plate from the nail bed
DLSO- specimen taken from Nail bed and scrapings under nail
WSO-specimen taken from the nail plate
PSO-specimen taken from the proximal nail bed
Microscopic evaluation of a potassium hydroxide preparation of the specimen only detects the presence or absence of fungi. Cannot specify which pathogen is present. Stain may help identify presence of fungi.
The only method of determining which genus and species of fungi is responsible for the infection.
Periodic Acid-Schiff (PAS)
Pathologist uses a fungal stain to help identify the presence of fungi. Like KOH, does not identify the specific pathogen.
Negative mycology lab test (negative KOH and negative Culture)
No residual involvement of the target nail
a predetermined percentage (80%-100%) of the nail that is visibly free of infection
No residual clinical involvement of the target nail
mycological cure (negative KOH and negative Culture)
Thickened epitheliun at the base of a fingernail or toenail from which a new nail substance develops.