cutaneous mycoses. case study

Dermatophytes(Superficial Mycoses)

Cutaneous Mycoses

Dermatophytes

•The superficial (cutaneous) mycoses are usually confined to the outer layers of skin, hair, and nails, and do not invade living tissues.

• The fungi are called dermatophytes.

•Dermatophytes fungi produce extracellular enzymes (keratinases) which are capable of hydrolyzing keratin.

ETIOLOGIC AGENTS

Microsporum species (13 species) (Skin, hair)

Trichophyton species (19 species) (Hair, skin, nails)

Epidermophyton floccosum(Skin, nails)

Microsporum

• Microsporum species form both macro- and microconidia on short conidiophores.

• Macroconidia are hyaline, multiseptate, variable in form, fusiform, spindle-shaped to obovate.

• Microconidia are hyaline, single-celled, pyriform to clavate, smooth-walled, 2.5 to 3.5 by 4 to 7 um in size and are not diagnostic for any one species.

Trichophyton• Trichophyton is characterized by the

development of both smooth-walled macro- and microconidia.

• Macroconidia are mostly borne laterally directly on the hyphae or on short pedicels, and are thin- or thick-walled, clavate to fusiform.

• Microconidia are spherical, pyriform to clavate or of irregular shape

• Effects on human gives 'Malabar itch', a skin infection, consisting of an eruption of a number of concentric rings, forming patches caused by fungus.

Epidermophyton

• Epidermophyton is a genus of fungus causing superficial and cutaneous mycoses, including E. floccosum, a cause of tinea corporis (ringworm), tinea cruris (jock itch), tinea pedis (athlete’s foot), tinea barbae, tinea versicolor, tinea nigra and onychomycosis or tinea unguium, a fungal infection of the nail bed.

CLINICAL MANIFESTATIONS

Tinea corporis - small lesions occurring anywhere on the body.

Tinea pedis - "athlete's foot". Infection of toe webs and soles of feet.Appearance: inflamed, scaly, red and dry.

Tinea unguium (onychomycosis) – infection of nails. Can be a sign of HIV.Appearance: thick and scaly.

Tinea capitis - head. Frequently found in children.

Appearance: hair loss (alopecia) and cervical lymph node enlargement are common presentations. Edematous, crusting, scaly, well-circumscribed, black dot type; hair breaks off at scalp, leaves black dots .

Tinea cruris - "jock itch". Infection of the groin, perineum or perianal area.

Tinea barbae - ringworm of the bearded areas of the face and neck.

Appearance: Same as Tinea Capitis.

Malasezzia furfurTinea versicolor

(mild disease)

Tinea versicolor - Characterized by a blotchy discoloration of skin which may itch.

Tinea versicolor

(Spaghetti and

meatballs)

Disease Etiological Agent

Symptoms Indentification of organism

Tinea capitis

Microsporum sp. Trichophyton sp. Epidermophyton sp. ringworm

lesion of scalp

presence/absence and shape of micro- and macroconidia in scrapings from lesion

Tinea corporis

Microsporum sp. Trichophyton sp. Epidermophyton sp ringworm

lesion of trunk, arms, legs


Tinea manus


lesion of hand


Tinea cruris "jock itch"


lesion of groin


Tinea pedis"


athlete's foot" lesion of foot


Tinea unguium

Microsporum sp. Trichophyton sp. Epidermophyton sp

infection of nails


Diagnosis

• Clinical diagnosis (e.g Wood‘s lamp)

• laboratory diagnosis:

a) Microscopic examination of

(skin, nails, hair)

b) Culture (Sabouraud‘s agar)

Dermatophyte Culture

Trichophyton species

Large, smooth, thin wall, septate, pencil-shaped

Thick wall, spindle shape, multicellular

Microsporum species

Epidermophyton floccosum

Bifurcated hyphae with multiple, smooth, club shaped macroconidia (2-4 cells)

Common Medicines:

•Griseofulvin

•Clotrimazole

•Miconazole

•Ketoconazole

•Itraconazole

The commonly found fungal skin diseases

can be categorized into four kinds:• Fungi that only grow on the surface of skin or

hair cause the disease called superficial mycoses.

• Diseases like athlete foot or ringworm where only a superficial layer of the skin is damaged or infected are known as cutaneous mycoses or dermatomycoses.

• Diseases where the subcutaneous, connective, and bone tissue that lie under the superficial layer are affected are known as subcutaneous mycoses. These initiate with a trauma to the skin and are generally chronic in nature.

• The only fatal kind of mycoses is the Deep

or Systematic mycoses where even the

internal organs can be harmed badly by

Fungi and can also become widely

disseminated. These generally begin from

internal parts like lungs and slowly spread

to the other parts as well.

• The diseases that are not caused in the

regular course but are caused due to

inefficiency of Immune system of Human

Body are known as Opportunistic mycoses.

MODE OF TRANSMISSION

Cutaneous mycoses•infections strictly confined to

keratinized epidermis (skin, hair, nails) are called dermatophytoses - ringworm & tinea

39 species in the genera Trichophyton,• Microsporum, Epidermophyton

communicable among humans, animals, & soil infection facilitated by moist and chafed skin.

• Ringworm of scalp (tinea capitis) affects scalp & hairbearing regions of head; hair may be lost

• Ringworm of body (tinea corporis) occurs as inflamed, red ring lesions anywhere on smooth skin

• Ringworm of groin (tinea cruris) “jock itch” affects groin & scrotal regions

• Ringworm or foot & hand (tinea pedis & tinea manuum) is spread by exposure to public surfaces; occurs between digits & on soles

• Ringworm of nails (tinea unguium) is a persistent colonization of the nails of the hands & feet that distorts the nail bed

Symptoms of Tinea Pedis

Athlete's foot causes scaling, flaking, and itching of the affected skin. Blisters and cracked skin may also occur, leading to exposed raw tissue, pain, swelling, and inflammation. Secondary bacterial infection can accompany the fungal infection, sometimes requiring a course of oral antibiotics.

Diagnosis• Athlete's foot can usually be diagnosed

by visual inspection of the skin.• a biopsy of the affected skin (i.e. a

sample of the living skin tissue) can be taken for histological examination.

• A Wood's lamp, is not usually helpful in diagnosing tinea pedis since the common dermatophytes that cause this disease do not fluoresce under ultraviolet light. However, it can be useful for determining if the disease is due to a non-fungal afflictor.

TransmissionFrom person to person

-communicable disease.-transmitted in moist environments where people walk barefoot, such as showers, bath houses, and locker rooms -transmitted by sharing footwear with an infected person, or less commonly, by sharing towels with an infected person.

Case discussion

L.J., a 23 yr old male, single, and a professional basketball player, came to the physician's office due to severe itchiness oh

his feet.

History of past Illness The condition started around 3

weeks prior to consultation, when he noted itchiness in his feet, especially in the areas in-between his toes. it involved scaling in the said areas, as well as slight redness, which later spread to the rest of his feet.

Review of Systems No noted fever, headache, difficulty of

breathing, chest pains, abdominal discomfort nor swelling in other parts of the body.

PAST MEDICAL HISTORY AND FAMILY MEDICAL HISTORY

The patient as not previously diagnosed with diabetes, asthma, hypertension, or heart disease. There was note of an incidental finding of heart disease in his grandfather. The rest are unremarkable.

PERSONAL,SOCIAL AND OCCUPATIONAL HISTORY

L.J. works as a professional basketball player. He is sure he did not wade in flood waters recently. He also could not recall ever being bitten by any animal for the past two months. He, however, admitted he noticed his team mate came up with similar symptoms a few weeks before he experienced the same thing. They share lockers.

Physical ExaminationThe patient had a BP of 110/80 mmHg, a heart rate of 72bpm, afebrile, had pink conjunctivae, anicteric sclerae and no noted cervical lynphadenopathies. His breath sounds were equal, clear, with no noted rales nor wheezes . He had an adynamic precordium, normal rate and regular rhythm, with no noted murmurs. Abdomen was soft, non-tender. His extremities had pink nail beds, he had full and equal pulses with no signs of edema. Examination of his feet, however, revealed erthyma and scaling, which is more concentrated in his soles and in between his toes.

Prevention at home• Bathroom hygiene • Frequent laundering

Wash sheets, towels, socks, underwear, and bedclothes in hot water

• Avoid sharing• Prevention measures in public places

Wear shower shoes in public places and make sure you wash feet, especially in between toes then dry thoroughly.

Personal prevention measures • Wear lightweight cotton socks to help

reduce sweat. • Dry feet well after showering, paying

particular attention to the web space between the toes.

• Keep shoes dry by wearing a different pair each day.

• Do not use socks that are not yet washed.

Treatment

cutaneous mycoses. case study

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