Trichophyton mentagrophytes - Clinical Manifestation

Clinical Manifestation of Trichophyton mentagrophytes

Clinical manifestations of Trichophyton mentagrophytes infection include:

1. Tinea capitis (kerion)

2. Tinea pedis

3. Tinea barbae

4. Tinea manuum

5. Tinea cruris

6. Folliculitis

7. Extensive granuloma – mostly in immunocompromised (eg Cushing syndrome)

8. Id reaction

Tinea capitis

• tinea capitis, caused by Trichophyton mentagrophytes, 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 mentagrophytes is the causative agent of the condition known as kerion

Kerion

• host immune response against Trichophyton mentagrophytes infection of the scalp (hair follicles) results in an actual inflammatory reaction known as kerion

• can be accompanied by secondary bacterial infections

• typically affects children

• appears raised with spongy lesions (honeycomb)

• a painful condition with deep suppurative lesions on the scalp with pus discharge from follicles, sinus formation, and production of mycetoma-like grains (rare)

• also associated with inflammation of the lymphatic vessels (lymphangitis, lymphadenitis) and fever

Tinea pedis

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

Tinea barbae

• tinea barbae, caused by Trichophyton mentagrophytes, is the fungal infection of the hair around the bearded area

• clinically manifests as cutaneous granulomatous lesion (chronic inflammatory reaction) or  a follicular inflammation

• an important cause of folliculitis

• most common among agricultural workers (animal-to-human transmission)

• human to human transmission is less common

• affected area manifests as a pimple or blister, swelling and redness, and lumpy skin with crusting around hairs in the infected area

• in some cases, can be itchy and painful

• hairs on the infected area are effortless to pull out

Tinea manuum

• tinea manuum, caused by Trichophyton mentagrophytes, is a fungal infection of the hand

• maybe caused by transmission from other fungal infections such as athlete's foot or tinea cruris

• scaling is diffused on the palms or back and each rash looks different

• more prominent palmer creases which appear white in chronic cases

• nails may also be infected

• maybe itchy, look slightly raised with dry flaky thick skin on hand’s palm

• in cases where the back of the hands are infected, reddish circles resembling ringworm are present

• mostly only one hand is affected but Trichophyton mentagrophytes infection may occur on both hands

Tinea cruris

• tinea cruris, caused by Trichophyton mentagrophytes, is also known as jock itch, ringworm of the groin, scrot rot, eczema marginatum, gym itch, crotch itch

• it is a superficial fungal infection of the groin (upper inner thighs), and buttocks which are contagious and occurs predominantly in hot-humid climates

• symptoms include intense itchy red rash with a raised, scaly, and well-defined curved border

• may have some blistering, and weeping, with light colored center

• the rash may appear as flaking, peeling, iridescence, cracking, rippling skin which may appear tan, brown, or reddish in color

• hair follicles may also be involved resulting in papules, nodules, and pustules within the plaque

• in chronic cases, these plaques may reach the scrotum in men, mons pubis, and labia majora in women

• in the case of individuals using steroids for immunosuppression, the penis may also be affected

• the infection may also extend to the anus

Folliculitis

• Trichophyton mentagrophytes infection may result in folliculitis

• may occur anywhere on hair-covered skin

• the condition appears as pimples with white tips

Id reaction

The infected individual becomes hypersensitive to constituents of Trichophyton mentagrophytes and may develop dermatophytids. Dermatophytids are allergic manifestations associated with vesicles of the fingers and elsewhere on the body, especially the hands.

This condition is a response to circulating fungal antigens and the lesions do not contain fungal hyphae. Trichophytin skin test can detect this reaction.