Dermatophytosis (B35)
ICD-10 code B35 covers dermatophytosis, a group of fungal infections affecting the skin, hair, and nails. These codes specify various types and locations of fungal infections commonly referred to as tinea.
The ICD-10 code for dermatophytosis includes subcodes that help identify the exact type of infection by its site or causative organism. For example, B35.0 is used for tinea barbae and tinea capitis, infections of beard and scalp hair often caused by Trichophyton or Microsporum species. B35.1 represents tinea unguium, also known as onychomycosis, which affects the nails and can involve fungi like Trichophyton rubrum. Infections involving hand skin (tinea manuum), foot skin (tinea pedis or athlete’s foot), and body skin (tinea corporis) are coded under B35.2, B35.3, and B35.4 respectively. Less common types like tinea imbricata (B35.5) and tinea cruris (B35.6), affecting groin skin, have dedicated codes. The category B35.8 covers other less typical dermatophyte infections such as tinea faciei and deep-seated dermatophytosis. If the infection is unspecified, coders use B35.9. Using these codes correctly helps distinguish between the many clinical and fungal variants of dermatophyte infections for precise medical documentation and treatment planning.
Instructional Notations
Includes
This note appears immediately under a three character code title to further define, or give examples of, the content of the category.
- favus
- infections due to species of Epidermophyton, Micro-sporum and Trichophyton
- tinea, any type except those in B36
Clinical Terms
The following clinical terms provide additional context, helping users better understand the clinical background and common associations for each diagnosis listed in this section. Including related terms alongside ICD-10-CM codes supports coders, billers, and healthcare professionals in improving accuracy, enhancing documentation, and facilitating research or patient education.
Onycholysis
Separation of nail plate from the underlying nail bed. It can be a sign of skin disease, infection (such as ONYCHOMYCOSIS) or tissue injury.
Onychomycosis
A fungal infection of the nail, usually caused by DERMATOPHYTES; YEASTS; or nondermatophyte MOLDS.
Tinea Capitis
Ringworm of the scalp and associated hair mainly caused by species of MICROSPORUM; TRICHOPHYTON; and EPIDERMOPHYTON, which may occasionally involve the eyebrows and eyelashes.
Tinea Cruris
Fungal infection of the groin. The main causative fungus is TRICHOPHYTON.
Tinea Favosa
A disease of the scalp that may affect the glabrous skin and the nails and is recognized by the concave sulfur-yellow crusts that form around loose, wiry hairs. Atrophy ensues, leaving a smooth, glossy, thin, paper-white patch. This type of disease is rare in the United States and more frequently seen in the Middle East, Africa, Southeastern Europe, and other countries bordering the Mediterranean Sea. (Arnold, Odom, and James, Andrew's Diseases of the Skin, 8th ed, p319)
Tinea Pedis
Dermatological pruritic lesion in the feet, caused by Trichophyton rubrum, T. mentagrophytes, or Epidermophyton floccosum.
Trichophyton
A mitosporic fungal genus and an anamorphic form of Arthroderma. Various species attack the skin, nails, and hair.
