BACTERIAL SKIN INFECTIONS FOR PRIMARY HEALTH CARE WORKERS

Digafe Tsegaye MD ,Dermato-venerologist Hon. Assistant Professor at MMS

Introduction

The normal skin of healthy individuals is highly resistant to invasion by the wide variety of bacteria to which it is constantly exposed.

NATURAL RESISTANCE OF THE SKIN Mechanical barier Low PH (5.5) Relative dryness of the skin Sebum : antibacterial activity unsaturated long-chain fatty acids ,free fatty acids (linoleic and

linolenicacids) Sweat :?? IGM ,IGA ,IGD Normal flora

Most of the bacterial skin infections are caused principally by two organisms

These are Staphylococcus aureus Group A streptococcus

Others include coryenebacterium ,mycobacterium ,closteridia, bacillus anthracis

Common primary bacterial skin infections( PYODERMAS)

S.aureus

Impetigo

Folliculitis

Furuncle

Carbuncle

Ecthyma

Paronychia

Scarlet fever

SSSS

TSS

S.pyogenes

Erysipella

Cellulitis

Scarlet fever

Lymphangitis

Thrmbophlebitis

Necrotizing fascitis

TSS

Impetigo

Non- bullous

Bullous

Non bullous impetigo • Accounts 70 % of impetigo • Children of all age group are affected • Constitutional symptoms are abscent • Etiology : Group A Streptococcus • Presents as honey colored or yellowish colored crusted

lesions • Complicates skin conditions such as scabies ,eczema

,tinea capitis …

• RX : cloxacilline , Augumentine , cefalexine

Impetigo on the scalp

Yellowish crustes on the face

What do you see ?

What do you see ?

Impetigo complicating Eczema

What do you see ?

Impetigo complicating eczma

Bullous impetigo

• Affects infants • Caused by S.aureus ( toxin producing)

• Presents clinically as blistering lesions ( Bullae) , or Errosions

• RX : topical antibiotics +, Cefalexine , Augmentine or cloxacillne

Turbid bullous lesions

What do you see ?

FOLLICULITIS

A pyoderma that begins within the hair follicle

Superficial/Bockhart's impetigo/

Deep /Sycosisbarbae/ Rx : local +systemic

antibiotics

What do you see ?

FURUNCLE AND CARBUNCLE

A furuncle or boil is a deep-seated inflammatory nodule that develops about a hair follicle, usually from a preceding, more superficial folliculitis and often evolving into an abscess. Arise in hair-bearing sites,

particularly in regions subject to friction, occlusion.

They may complicate preexisting lesions

carbuncle

Is formed when two or more furuncles join each other

Systemic symptoms are often present such as fever ,maliase

RX : systemic antibiotics ( Cloxacilline ,cefalexin ,Augmnetine) + incission and drainage

Ecthyma

Ecthyma is usually a consequence of neglected impetigo

Untreated staphylococcal or streptococcal impetigo can extend more deeply, penetrating the epidermis, producing a shallow crusted ulcer

The lesions are slow to heal, requiring several weeks of antibiotic treatment for resolution

ecthyma

Acute paronychia

Rx : cloxacilline 500 mg po qid for 7 dyas

Incise and draine the abscess

Erysipelas

A distinct type of superficial cutaneous cellulitis with marked dermal lymphatic vessel involvement caused by group A beta-hemolytic streptococcs.

New born –GB Streptococcus

Rarely ; S.aureus

Cellulitis

Involves more of the soft tissues, extending deeper into the dermis and subcutaneous tissue.

Group A streptococci are by far the most commonetiologic agents

But occasionaly GBSC in neww born

,Gm- in immunocompromised ,.. RX: rest ,po /Iv antibiotics

Gangrenous cellulitis/Necrotizing fasciitis

Characterized by necrosis of the epidermis and deeper soft tissue structures including muscle

Characteristically rapidly developing, progressive, and accompanied by constitutional symptoms, severe pain, and tenderness, with changes in overlying skin that progress to bulla formation and frank necrosis.

Etiology : group A streptococci, histotoxic Clostridia (including C. perfringens, C.

septicum , anaeeobes DM ,operative /traumatic wounds , malnutrition MR :40 to 50 percent

Rx : surgical debridement amd pareentral antibiotics

Other infections caused by Streptococcus

Acute lymphangitis

Scarlet fever

Ecthyma

Streptococcus intertrigo Blistering distal dactylitis

Guttate psoriasis

Erythema marginatum

Purpura fulminans

Erythema multiforme like lesions

Erythrasma.

well-defined but irregular reddish brown patches, occurring in the intertriginous areas, or by fissuring and white maceration in the toe clefts.

Corynebacterium minutissimum Wood lamp examination of

erythrasma reveals a coral-red fluorescence caused by coproporphyrin III.

Pitted keratolysis

involves the stratum corneum of the web spaces and plantar surface.

Etio ; Micrococcus sedentarius

Rx : fusidic acid cream (Foban cream/erythromycin 500 mg qid for 7 days

Give treatment for hyperhidrosis

Trichomycosis axillaris and pubis

bacterial infection of the hair shaft

nodular thickenings on the hair shaft, composed of colonies of aerobic Corynebacterium.

Benzoyl peroxide wash and gel are effective as treatment and prevention against recurrence of trichomycosis.

Other less common infections

Anthrax Caused by B. anthracis

Disease is acqired from contaminated meat , skin of infected animals

Painless Swelling with central black eshar

Rx : po doxycline 100mg po bd for 3 weeks

Bacillary angomatosis

Etiology : Bartonella henselae

Exclusively present in HIV pts

RX : erythromycin 500 mg po qid for three weeks

Cutaneous TB

Is rare but not uncommon

Presents in many ways Scrofuloderma is the

most common type May be inoculated

from outside or spread from distant or adjacent organs

Mode of acquistion Hematogenous spread Lymphatic spread Direct inoculations Direct extenesions Hypersensitivity to

mycobacterium tb

Types of cutaneous TB

Tuberclosis chancre Tuberclosis verucosa

cutis Orificial tuberculosis Scrofuloderma

Lupus vulgaris

Mtestatic tuberclosis abcess

tuberclids

Lupus vulgaris

Tb lymphadenitis Lupus vulgaris

Lupus vulgaris

TB of the skin

TB osteomyelitis with skin involvement

Scrfuloderma

TB verrucosa cutis

Investigation and Treatment

Cxr ,CBC , ESR, Biopsy Category III anti-tb drugs

Tetanus Caused by closteridia tetani Anerobic gram negative bacteria Conatminate necrotic and devitalized wound May cause muscle spasm and respiratory failure Treatment High dose crystalline pencillne , diazepam Prevention : TAT