Transcript Fungal Infections of the skinx

Skin fungal infections
 Clinical Skin fungal infections are generally divided into
 Superficial
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Tinea versicolor, Piedra (Trichosporosis), and Tinea nigra
 Cutaneous
 Dermatophytosis, Candidiasis of skin, mucosa, nails and others
 Subcutaneous
 Mycetoma, Sporotrichosis, Chromoblastomycosis, and others
Superficial Mycoses
 Defined as infections in which a pathogen is restricted to
the Stratum corneum, with little or no tissue reaction
 These affect the uppermost dead layers of skin or hair shaft
 They are painless and usually do not provoke the immune
system
 They include
 1- Tinea versicolor
 2- Tinea nigra
 3- Piedra
Tinea Versicolor
 Tinea versicolor is a long-term (chronic) fungal infection of the
skin
 The fungus interferes with the normal pigmentation of the skin
 resulting in small, discolored patches
 The most common sites
 The back, underarms, upper arms, chest, and neck
 Tinea versicolor occurs most frequently in teens and young
adults
 Sun exposure may make tinea versicolor more apparent
 Tinea versicolor often recurs, especially in warm, humid weather
Clinical presentation:
 Tinea versicolor is a type of infection of the keratinized
epithelial cells in the stratum corneum.
 Hypo- or hyperpignented macules on chest or back.
 The infection causes patches of discolored skin that
may be:
 Colored white, pink, tan or dark brown
 Slow-growing, scaly and mildly itchy
 More noticeable after sun exposure
Causes
 The fungus that causes Tinea versicolor can be found on
healthy skin (normal flora of skin).
 It only starts causing problems when the fungus overgrows
 A number of factors may trigger this growth, including:
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Hot, humid weather
Excessive sweating
Oily skin
Hormonal changes
Weakened immune system
 Malassezia furfur, and Malassezia globosa
 It is a Yeast
 Lipophilic
 Normal flora of skin
 Diagnosis
 Skin scraping
 Potassium hydroxide (20% KOH)
 Positive for short hyphae
and yeast cells
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Spaghetti and meatballs
 Culture
 Malassezia furfur
 Oil should be added to the media
Pityriasis versicolor commonly causes
hypopigmentation in people with dark
skin tones
Superficial Mycoses
Tinea nigra:
 Superficial fungal infection
 Causes dark brown to black painless
patches (macule) on the palms of the hands and the
soles of the feet.
 This infection is caused by the fungus formerly
classified as Exophiala werneckii
 More recently classified as Hortaea werneckii
 Skin scrapings
 In 10% or 20% KOH will show
brown septate hyphae
 The KOH lyses
the nonfungal debris
 Culture on SDA & Mycobiotic
Agar plate with the dominant fungi in the
salterns, the black yeast Hortaea werneckii
Diagnosis
 produce melanin in their cell walls
Micrograph of the fungus
Hortaea werneckii
 growth of dematiaceous fungus
Superficial Mycoses - Piedra
 Asymptomatic infection of the hair shaft, causing nodules
on the hair shaft
 On scalp hair, and other body hair.
 Black piedra (Exothrix infection)
 Piedraia hortae
 Dark pigmented nodules
 Hard and firmly attached to hair shaft
 White piedra( Endothrix infection)
 Trichosporon beigelii
 Lightly pigmented, white to brown nodules
 Soft, loosely attached
N
Laboratory diagnosis
 1. Clinical Material
 2. Direct Microscopy
 Hairs should be examined
using 10% KOH
White piedra
 Epilated hairs with white soft nodules present on the shaft
 Sabouraud's dextrose agar (SDA)
Hair with black Piedra
 3. Culture
Treatment of Superficial infections
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2% salicylic acid
3% sulfur ointments
Whitfield's ointment
Ketoconazole
 Piedra
 Cutting or shaving the hair
 Or apply 2% salicylic acid
 Or 3% sulfur ointment
 Nizoral shampoo (contains Ketoconazole)
 Antifungal agents
 Topical
Dermatophytosis
 Fungal infections of the Keratinized tissues of the
body (mainly: Stratum corneum, Skin epidermis,
and dermis could be involved).
 Scalp, glabrous skin, and nails caused by a closely
related group of fungi known as dermatophytes
 They are primary pathogens
 Contagious
 Direct contact between infected humans or animals
(goats, sheep, camel, cows, horses)
 Transfer form one area of the body to another
 Familial cross infection occurs
 Tinea (Ringworm): Classified according to site of inf:
 T. capitis
scalp
 T. corporis
glabrous (body) skin
 T. pedis
foot (Athlete’s foot)
 T. cruris
groin
Dermatophytes Etiology
 A group of related fungi called dermatophytes
(filamentous fungi; septate hyphae and conidia):
 Microsporum
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infections on skin and hair
 Epidermophyton
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infections on skin and nails
 Trichophyton
infections on skin, hair, and nails
Keratin - utilizing on hosts - humans
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Tinea Capitis
 Ringworm of the scalp (Tinea capitis) is a fungal infection of the
scalp hair and epidermis.
 Highly contagious infection
 most common in toddlers and school-age children
 Treatment for ringworm of the scalp includes
 medications taken by mouth
 medicated shampoo
 Some cases of ringworm of the scalp result in severe
inflammation at the site of infection
 that may cause scarring or permanent hair loss
Clinical presentation:
 Papules are solid raised skin lesions with defined
borders (less than 1 cm).
 One or more round patches (Erythematous papules)
of scaly skin where the hair has broken off or just
above the scalp.
 Patches that slowly expand or enlarged
in circular
appearance
 Scaly, gray or reddened (inflamed) area.
 Brittle or fragile hair that easily pulls out
 Tender or painful areas on the scalp.
Tinea capitis
Causes
 Ringworm of the scalp is caused by one of several
varieties of mold-like fungi called dermatophytes
 Microsporum canis or Microsporum gypseum
 Epidermophyton floccosum.
 Trichophyton mentagrophytes.
Methods of transmission
 Ringworm is contagious and can spread in the following
ways:
 Human to human
direct skin-to-skin contact with an infected person
 Geophilic species
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Keratin - utilizing soil saprophytes
 Object to human: Anthropophilic species
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clothing, towels, bed linens, combs or brushes
 Animal to human : Zoophilic species:
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dogs and cats, especially kittens
cows, goats, pigs and horses
Complications
Kerion
Kerion is the result of the host's response to a fungal ringworm infection of the hair
follicles of the scalp with secondary bacterial infection.
Tests and diagnosis
 Tests typically include a visual exam
 Sometimes, you may take a sample of the hair or skin
 History
 Close contacts, duration.
 Morphology of lesion
 Broken hairs, black dots, localized
 Woods Lamp
 Blue green
 Culture
Tinea Capitis - Treatment
 Must treat hair follicle
 Topical , but might be not effective
 Systemic agents
 Griseofulvin for children – is taken by mouth as a liquid or tablet
 Side effects
 Sensitive skin
 Terbinafine
 You may prescribe one of these medications for six weeks or
more
Tinea Corporis - Ringworm (body)
 Ringworm of the body is one of several forms of
ringworm, a fungal infection that develops on the
top layer of the skin
 It's characterized by an itchy,
red circular rash with
healthy-looking skin in the middle
 Ringworm gets its name from
the characteristic ring that
can appear
Ringworm on the arm
Clinical presentation:
 A circular rash on the skin that's red and inflamed
around the edge and healthy looking in the middle
 Slightly raised expanding rings of
red patches, scaly skin on the trunk or face
 A round, flat patch of itchy skin
Causes
 Microsporum canis or Microsporum gypseum
 Epidermophyton
floccosum.
 Trichophyton
mentagrophytes;
(Micro-and Macroconidia;
Lactophenol-cotton blue)
 Risk factors predisposing for dermatophytosis:
 Living in humid or crowded conditions
 Have close contact with an infected person or animal
 Share clothing, bedding or towels, with fungal infection
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patient
Sweat excessively
Participate in contact sports, such as wrestling, football or
rugby
Wear tight or restricted clothing
Have a weakened immune system
 Complications
 A fungal infection rarely spreads below the surface of the skin
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People with weak immune systems, may find it difficult to get rid
of the infection
Tests and diagnosis
 You will determine if patient have ringworm or another skin disorder
 skin scrapings or samples from the infected area and look at them
under a microscope
 a procedure known as a potassium hydroxide (KOH) test
 If a sample shows fungus, treatment may include an antifungal
medication
 If the test is negative but you still suspects that patient have ringworm,
a sample may be sent to the laboratory for testing
 this test is known as a culture
 you may also order a culture if condition doesn't respond to treatment
Candidiasis (Yeast Infection)
 Candidiasis is a fungal infection that can affect areas
such as the:
 Skin
 Genitals, Throat
 Mouth, Blood.
 Overgrowth of a type of yeast called Candida,
usually Candida albicans
 Dimorphic fungi that is
normally found
in human body.
Oral Candidiasis (Thrush)
 A yeast infection of the mouth or throat area is called thrush
 Healthy adults do not usually get thrush. It is most often seen in:
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Infants
Elderly
Patients getting chemotherapy
People with AIDS or other conditions that weaken the immune
system
 It can also be seen in
 people with diabetes
 in those who take antibiotics
 asthma inhalers with steroid medication
Oral candidiasis in a child
Yeast Infection of the Genitals
 Vaginal yeast infections are common in women. Common symptoms
include:
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Extreme itching in the genital area
Soreness and redness in the genital area
White, clumpy vaginal discharge
Painful intercourse
 But men can get a yeast infection, too. Symptoms in men include:
 Red rash on genitals
 Itching or burning on the tip of the genitals
 It is important to get treated for a genital yeast infection. You may pass
the infection back and forth to a sexual partner
Subcutaneous Fungal Infection
A-Sporotrichosis:
Caused by Sporothrix schenkii.
B-Mycetoma (Madura foot):
-Localized skin abscess due to granulomatous
infection of dermis and subcutaneous tissue.
-Caused by:
1-Pathogenic soil fungi: Madurella mycetomatis.
2-Bacteria: Actinomycetoma:
Actinomyces species or Nocardia.
Subcutaneous Fungal Infection
Madura Foot
Chromoblastomycosis
Sporotrichosis
Mycetoma