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Onychomycosis (cont.)

What Are Fungal Nail Infection Symptoms and Signs?

Patient Comments
  • Fungal nail infection usually does not cause any symptoms (painless) unless the nail becomes so thick it causes pain when wearing shoes. People with fungal nail infection usually go to the doctor for cosmetic reasons, not because of physical pain or problems related to fungal nail infection.
  • As the nail thickens, however, fungal nail infection may interfere with standing, walking, and exercising.
  • Paresthesia (a sensation of pricking, tingling, or creeping on the skin having no objective cause and usually associated with injury or irritation of a nerve), pain, discomfort, and loss of agility (dexterity) may occur as the disease progresses. Loss of self-esteem, embarrassment, and social problems can also develop.
  • Severe cases of Candida infections can disfigure the fingertips and nails.

Symptoms or signs (appearances) of fungal nail infection based on subtype

Fungal nail infection is divided into subtypes that can be identified based on where the infection appears to be located relative to the structure of the nail.

  • In distal lateral subungual onychomycosis (DLSO), the nail plate is thick with a cloudy appearance (opaque), the nail bed underneath the nail thickens (becomes raised) and hardens (nail bed hyperkeratosis), and the nail separates from the bed underneath (onycholysis). The nail can be discolored and appear in a range from white to brown. The edge of the nail becomes severely eroded (ragged and brittle) and may become flaky (peeling).
  • In endonyx onychomycosis (EO), the nail plate has a milky white discoloration, but unlike DLSO, the nail does not separate from the bed (no onycholysis). The area under the nail (subungual area) does not thicken or harden (no hyperkeratosis).
  • White superficial onychomycosis (WSO) is usually confined to the toenails. Small white speckled or powdery-looking patches appear on the surface of the nail plate. The nail becomes rough and crumbles easily (crumbly nails).
  • In proximal subungual onychomycosis (PSO), an area of white spotting, streaking, or discoloration (leukonychia) develops near the nail fold and may extend to deeper layers of the nail. The nail plate becomes white near the cuticle and remains normal at the end.
  • In total dystrophic onychomycosis, the nail is thickened, opaque, and yellow-brown and/or greenish-brown to black. The entire nail plate and matrix are affected.
  • Yeast infection (Candida albicans), while affecting the nail, can appear with additional signs. Candidal infection can occur in the toenails and the fingernails but may also infect the tissue that surrounds the nail. The nail fold becomes inflamed (erythematous), or the nail plate separates from its bed (onycholysis). The nail bed thickens and hardens (nail bed hyperkeratosis), and inflammation of the nail fold is observed in chronic mucocutaneous disease (disease of mucous membrane and regular skin). The affected fingers or toes start to look rounded on the ends, like drumsticks, and, sometimes, the entire thickness of the nail becomes infected.
  • Some fungal infections may be associated with an odor described as a slightly foul odor or a "cheesy" odor. This odor may be due to chemicals (S-methyl thioesters) produced by bacteria that can colonize fungal-infected and other warm, damp areas.
Picture of fungal nail infection on the big toes
Picture of fungal nail infection on the big toes; SOURCE: CDC/Dr. Edwin P. Ewing, Jr.

Medically Reviewed by a Doctor on 2/2/2016

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Onychomycosis »

Onychomycosis (OM) refers to a fungal infection that affects the toenails or the fingernails.

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