Download Bacterial skin infections

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 Bacillus anthracis.. Cutaneous Black Lesions..
 Clostridium perfingens and other sp. : Necrotizing
Fasciitis.. Myonecrosis, Cellulitis, tissues putrefaction,
gas production/ Gas gangrene.. Surgical/Traumatic
wound.. Skin- Subcutaneous (Mixed Infection)..
Specific Enzymes & Exotoxins
 Borrelia Burgdorferi : Lyme disease .. Transmitted
by Tick/ Insect bites.. Incub. 1-3 weeks.. Annular
Rash.. Chronic Skin Lesion.. Cardiac & Neurological
Abnormality.. Arthritis.. Endemic USA, China, Japan
 Bartonella species: G-ve bacilli Bartonellosis Cat
Scratch Fever..followed Cat scratch or bite..Skin
lesions.. Subacute regional lymphadenitis..Septicemia.
Tuberculosis-Leprosy-1
 Cutaneous Tuberculosis (TB).. Cutaneous TB is a
relatively uncommon form of extra-pulmonary TB..
 Rare M. tuberculosis.. Common M. marinumulcerans.. Low Temperature..Water.. Skin Lesions..
Chronic cutaneous ulcer.. Small granulomas Follow
skin injury..Trauma.
 Leprosy: Chronic bacterial infection caused by
M. leprae.. It primarily affects cold body sites skin,
mucous membranes.. peripheral nerves ..nose, ears,
eye lids and testes.
 characterized by multiple skin lesions accompanied
first by sensation loss/ anesthesia.. sensory loss in the
affected areas, toes, finger tips, tissue destructions.
Leprosy-2
Leprosy-3
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 Lebrosy can affect people of all races around the
world. However, it is most common in warm, wet
areas in the tropics and subtropics.
 In most cases, it is spread through long-term
contact with a person who has the disease but
has not been treated.
 Most people will never develop the disease
even if they are exposed to the bacteria.. have
a natural immunity to leprosy.
 Worldwide prevalence is reported to be around 5.5
million, with 80% of these cases found in 5 countries:
India, Indonesia, Myanmar, Brazil and Nigeria.
Clinical Leprosy-4
 Infection incubation period range from 6 months - 40
years or longer. usually begins in the extremities
 Leprosy forms depend on the person's immune
response to the infection.
 There are several forms of leprosy:
 Tuberculoid form.. Mild Form.. Few AF Bacilli,
Lepromin skin test +ve, Presence nerve sensation
 lepromatous type Severe form.. Numerous Acid-fast
bacilli, Loss nerve sensation.. Lepromin skin test -ve
Diagnosis & Treatment
 Lab Diagnosis: A skin biopsy may show
characteristic granulomas (mixed inflammatory cell
infiltrate in the deeper layers of the skin, the dermis)
with involvement of the nerves.
 Presence Acid fast bacilli.. number of bacilli visible
depending on the type of leprosy.. No Culture.. No
Protected Vaccine available.. BCG may help &
reduce the severity of disease
 Treatment: Dapsone, Rifampin, Clofazimine. Life-long
Treatment ..No Cure but Less Tissue Damage and
Spread of Infection.
Common Fungal Skin Infection-1
 Superficial & Cutaneous Mycosis: Invade only dead
tissues of the skin.. keratinized body tissues.. Skin,
Hair, Nails. causes skin peeling, redness, itching,
burning.. less blisters and sores.
 Malnourishment, poor hygiene, suppressed immunity
& warm moist climate may increase the incidence
fungal skin infection
 Dermatophytes: Trichopyhton, Microsporum,
Epidermatophyton spp., Yeast forms Piytrosporum,
Trichosporons ..present in hair follicles & skin folding.
 Transmission: Usually from person to person or
animal to person.. dust particles..common more with
chronic skin disorders.
Tinea Corporis
Tinea pedis -Tinea capitis kerion
Skin Fungal Infection-2
 Tinea capitis: Hair follicles, scalp circular patches..
Scaling, Hair Loss..Children..Rare adults
 Tinea corporis: Skin annular-erythematic lesions,
Vesicles, Scaling.. Itching.. Rash.. All Ages.. Mostly
caused by Dermatophytes ..rarely mixed with Yeast
 Tinea pedis : Red vesicles.. Interdigital spaces, web
lesions, Toes, Plantar surface.. Feet, Itching.. Chronic
lesions..Wearing tight shoes/socks, increased feet
sweating.. More in Adults than children.. Cased by all
Dermatophytes.
 Tinea cruris: Pelvic area.. Groin.. Erythematic
Lesions, Itching, Chronic.. more common in male
young adults..mostly Epidermophyton spp
Skin Fungal Infection-3
 Tina unguium (Onychomycosis): Mostly caused by
Trichophyton ,Microsporum.. less Candida..fingernails
& toenails. Nails become colorless/dark colored,
thicken, disfigure and brittle..Diabetes
 Psoriasis is a common skin disorder produces thick
red plaques covered with silvery scales..can affect the
nails, scalp, skin and joints..not caused by fungus and
not transmitted to others.
 Eczema develops due to multiple immunological &
other medical conditions.. Skin becomes inflamed or
irritated..No infectious agent involved.
 Aspergillus & Cryptococcus spp. Rare cause localised
skin or nail..
Onychomycosis-Psoriasis
Skin Fungal Infection-3
 Tinea Versicolor/Pityriasis: Malassezia furfur /
Piytrosporum folliculitis.. Lipophilic Yeast
..difficult to culture in Labs. Part skin flora..
Endogenous infection.. Skin Moist-Folded
Area.. Discoloration.. Red Spots.. Mostly FaceNeck Finger Trunk..Mild..rarely Chronic, Stress
conditions, UV-Light, Common in young adults.
 Head dundruff, Seborrheic dermatitis.
 White & Black Piedra..Trichosporon spp., Soft
to hard nodules. scalp hair & hair shaft , skin
face , any body part.
Yeat skin infection
 Candidasis: C. albicans, C. glabrata, C. tropicalis..
Other spp. Endogenous infection..moist folds of skin..
Lesions, finger nails, toenails, Finger webs.. Diabetes,
immuno-compromessed.. more common in Infant &
women.. Candida infections can look just like other
types of dermatitis /eczema or skin allergy. itching,
redness..infection
 Blasmycosis: Blastomyces dermatitidis &
Histoplasmosis : Histoplasma capsulatum..
Dimorphic Fungi.. Soil ..Spore Inhalation.. Respiratory
infection.. Systemic Infection.. Complications: Skin
ulcerations/lesions Granulomas..causes severe
damages..common USA, Canada
Tinea Pityrisis / versicolor
Seborrheic dermatitis
Lab diagnosis-4
 Direct microscopic examination of skin scales
dissolved in a 10 % solution potassium hydroxide
(KOH).. demonstrating the fungus as small Filaments /
Yeast like structures.
 Culture: Sabouraud Dextrose agar, Incubation at
room temperature & 37 C for 2-6 Weeks. . Slow
growth for Dermatophytes..Rapid growth Candida.
 ChromCandida agar.. used for rapid identification of
common Candida species.
 Treatment: Most skin infections respond very well to
topical antifungal drugs..Less systemic drug .. interact
with Ergosterol ..causing Fungal Cell membrane
disruption.. Imidazole drugs ..miconazole,
clotrimazole, econazole, ketoconazole, fluconazole