Trichophyton tonsurans - Clinical manifestation

Clinical manifestation of Trichophyton tonsurans

Clinical manifestations of Trichophyton tonsurans include Tinea capitis (most common), Tinea corporis, onychomycosis, and Tinea pedis.

Tinea capitis

• tinea capitis, caused by Trichophyton tonsurans, is a cutaneous fungal infection of the scalp

• this dermatophytosis is also known as herpes tonsurans, ringworm of the scalp, scalp ringworm, ringworm of the hair, tinea tonsurans

• fungal invasion of the hair shaft results in single or multiple patches of hair loss or a 'black dot' pattern due to broken-off hairs

• associated symptoms include thickening scaling, itching, pustules, dandruff (seborrheic dermatitis), boggy swelling, expanding red rings, and inflammation of the scalp

• may also lack clinical symptoms

• most common in pre-pubertal male children

• Trichophyton tonsurans is the causative agent of a condition known as a black dot

Black dot

• Trichophyton tonsurans invade hairs and abundantly sporulate in the hair shaft (endothrix).

• as a result, the infected hair bursts and curl with hair breaking off near the surface of the scalp, resulting in a black dot on the smooth scalp surface

Tinea corporis

• tinea corporis, caused by Trichophyton tonsurans, is a fungal infection of the body – the arms and legs

• more common on glabrous skin i.e. where there is a lack of hair but may occur on any superficial part of the body

• marked by enlarging raised red rings with a light central area (ringworm_

• symptoms include itching, an elevated rash with scaly touch, hair loss in the infected area

• the skin surrounding the rash appears dry and flaky

Tinea unguium

• Trichophyton tonsurans is one of the causative agents of tinea unguium

• also known as Distal subungual onychomycosis

• fungal infection of the nail (toenail or fingernail)

• invades the nail bed and underside of the nail plate

• symptoms include white, black, green, or yellow nail discoloration, thickening of the nail, separation of the nail from the nail bed

• in chronic cases, nails may become brittle with pieces or whole nails breaking off

• in untreated cases, the skin underneath and around the nail can become inflamed and painful

• no pain or other bodily symptoms unless the disease is severe

• does not necessarily require treatment but oral antifungal medicine is effective (associated with liver problems)

Complication of tinea unguium

A complication of tinea unguium, caused by Trichophyton rubrum, is cellulitis.

Tinea pedis

• tinea pedis, also known as athlete's foot, is a common clinical manifestation of Trichophyton rubrum infection

• infection of the foot, toes, interdigital web spaces

• warmth and moisture produced by the shoes aid in establishing and maintaining infection

• commonly seen in individuals wearing shoes for long hours

• symptoms include itching, scaling, cracking, redness, and in rare cases skin blisters to ulcerative 

• although any area of the foot may be infected, areas between toes are most commonly infected

• chronic cases may result in the moccasin foot in which the entire foot forms white scaly patches

• the moccasin foot is mostly asymptomatic with slightly erythematous plaques on the sole of the foot and is covered by hyperkeratotic scales

• can be divided into four categories -

  * chronic interdigital

  * plantar (moccasin foot)

  * acute ulcerative

  * vesiculobullous

Chronic interdigital

• most common

• occurs between toes

• syndromes include maceration, fissuring erythema, scaling in toe webs

• mostly found between the fourth and fifth toes

Plantar (moccasin foot)

• also known as the moccasin foot or hyperkeratotic

• occurs on the sole of the foot i.e. plantar and lateral surfaces

• associated with scaling or hyperkeratosis

Acute ulcerative

• usually affects the soles of the feet

• associated with maceration, denudation, oozing (pus) of the skin

• macerated lesions with scaly borders

Vesiculobullous

• less common mucocutaneous disease

• characterized by vesicles (less than 5-10mm), bullae (blisters) (larger than 5-10mm) formation

• these vesicles and bullae are fluid-filled lesions

• occurs near the instep and adjacent plantar surface

• pustules, which are sometimes formed, are small with clear vesicles

Complications of tinea pedis

In chronic cases, the skin may crack leading to bacterial skin infection and inflammation of the lymphatic vessels (lymphangitis, lymphadenitis). Trichophyton rubrum may also spread to infect the toenails resulting in a condition known as onychomycosis.

If the host develops a scratch reflex, it may lead to self-inflicted excoriations, and if not immediately washed, it may spread to other body parts/people or even infect nails.