Bacterial skin infections •1. Suppurative infections – pyoderma • • a) affecting free skin • epidermal (impetigo, ecthyma) • dermal (erysipelas, cellulitis) • b) affecting skin appendages • folliculitis • furuncle, carbuncle • •2) Other bacterial infections • • • • • Predisposing factors •Alteration of the normal skin flora •Skin trauma •Chronic dermatoses •Immunodeficiency •Corticosteroid therapy •Malnutrition •Peripheral vascular disease •Systemic disease ( diabetes) Causative agents •Normal flora: Common pathogens: Uncommon p.: • • •St. Epidermidis St.aureus Enterobacter sp. • •St.saprophyticus b hemol.streptoc. Str.faecalis • •Micrococcus Escherichia coli Providencia sp. • •Corynebacterium Proteus mirabilis Serratia sp. • •Propionibacterium Pseudomonas aerug. Bacteroides • acnes. Clostridium Streptococcus pyogenes •Group ( A-D,G) G+ cocci • • •toxins •DNase •Strepto • - kinase • •can trigger •guttate psoriasis Staphylococcus aureus •G+, spherical cocci • •destructive enzymes • • coagulase • proteases … • • •toxins: TSS toxin • enterotoxins – • SEA,SEB • •MRSA major problem in •hospitals • • • • • • Pyoderma • A) affecting free skin • •1) impetigo •2) erysipelas •3) cellulitis •4) necrotising fasciitis •5) chronic ulcerating pyoderma • • Pyoderma •B) affecting skin appendages • •1) folliculitis • a) superficial folliculitis • b) folliculitis simplex • c) folliculitis barbae • (sycosis barbae) • d) G- folliculitis • e) non infectious folliculitis Pyoderma • 2) furuncle/furunculosis • 3) carbuncle • 4) sweat gland infections • hidradenitis suppurativa • (5) nail fold infections paronychium • (6) eyelid infections – hordeolum • - blepharitis • - chalazion • • 1) impetigo •Non bullous: caused by str. pyogenes •Most common among children •Transferred by direct contact or subjects •Clinics: initially small vesicles, easily rupture, erosions covered with honey colored crusts •Treatment: wet coating, topical ATB: mupirocin, fusidic acid, rapamulin •Large areas, fever: systemic PNC, CFSP impetigo impetigo •Bullous impetigo: • •Caused by Staph. aureus producing exfoliatin A & B causing superficial separation in epidermis /str. granulosum/ •Clinics: flaccid blisters containing pus • face, groins, acral regions •Treatment: topical or systemic ATBs • • Bullous impetigo impetiginisation Staphylococcal scalded skin syndrome (Ritter) • •widespread superficial skin loss caused by staphylococcal exfoliatin •scarlatiniform rash aroud mouth,diaper area, •fever •flaccid blisters, easily rupture •Th: ATB, repl. of fluids,temp. control Staphylococcal scalded skin syndrome 2) erysipelas •Causative organism: Str. pyogenes (b hemolytic group A streptococci), less often other streptococci •Entry: minor injury, interdig. fissure, leg ulcers … •Clinics: prodromes (fever, chills) • warm painful red area with tongue like • extensions mostly leg, less often face •Variants: blistering erysipelas, haemorrhagic e., • abscessing e., necrotising e. •Complications: endocarditis, glomerulonephritis • •Treatment : procain G PNC i.m. 1,5 mil U 2 x d • alternatives: cephalosporins, macrolides • lincomycin • • erysipelas erysipelas 3) cellulitis •Agents: Strept. pyogenes,St.aureus •deeper infection than erysipelas •After minor injury,surgical wound erythema,with spared regions swelling,pitting edema •Regional lymphadenitis •Fever •Th: PNC, cephalosporins cellulitis 4) necrotising fasciitis •Agents: streptococcus pyogenes •If more agents: Synergistic necrotising fascitis/cellulitis •Older, IS patients •Erythema -->necrotic eschar • crepitation •Fever, extensive pain, •Th: surgical debridement •PNC+clindamycin or according to culture,iv Ig ! POOR PROGNOSIS ! necrotising fasciitis 5) chronic ulcerating pyodermas •Pyoderma ulcerosa,vegetans … • folliculitis Pyoderma aff.skin appendages: a) superficial folliculitis (ostiofolliculitis) Supperficial inflammation of the hair follicle (opening of the hair follicle) Staph. aureus Triggers: hot and humid weather sweating Trt: disinfectant sol topical ATB:Ery, clindamycin b) folliculitis simplex inflammation of the whole hair follicle Typical locations: Back, buttocks Scalp, axillae Itching Trt: disinfectant sol topical ATB:Ery, Clindamycin Large areas, fever: Systemic ATB: PNC, CFSP folliculitis simplex disseminata c) folliculitis barbae (syccosis barbae) Most common variant of ordinary folliculitis Pustules Nodules, abscesses Involving beard region and sides of the neck Starts with minor trauma Spreads by shaving Trt: disinfectant sol topical ATB:Ery, Clindamycin Large areas, fever: Systemic ATB: PNC, CFSP d) G- folliculitis •Chronic reccurent folliculitis of the mid-face region •Caused by G-bacteria •Enterobacter, E.coli,Klebsiella •Complication of acne, rosacea • •Th: quinolones: ciprofloxacin • + isotretinoin e) non infectious folliculitis • • •Folliculitis decalvans • •Perifolliculitis • capitis abscendens et suffodiens Furuncle (boil) Deep inflammatory nodule with central pus Develops from hair follicle infection Causative agent: St. Aureus Poor hygiene, diabetes, immunosupression Areas of friction Clinics: pustule --> nodule, central plug --> discharge of pus Healing with scar Trt: top. drawing oinments (ichtamol – saloxyl ung.) topical ATB:mup., fusidic a. Systemic ATB: PNC, CFSP Surgery: incision Furunculosis Multiple reccurent boils Predisposing factors: DM poor hygiene, immunosupression Atopic dermatitis nasal or perianal carriage of St. aureus Carbuncle Fusion of several boils Most common on the neck and trunk Inflammed swollen area Often with necrosis Treatment: systemc ATB surgery Carbuncle sweat gland infections - hidradenitis suppurativa • (5) nail fold infections • - paronychium • •Minor trauma of cuticle • •St.aureus • •Purulent secretion •from the nail fold • •Ddg: candidal paron. • herpetic whitlow • •Th: drainage • topical ATB (6) eyelid infections – hordeolum 2. Other bacterial infections •Cutaneous diphtheria - rare •Listeriosis - rare •Actinomycosis •Nocardiosis – mostly in immunosupressed pat. •Cat scratch disease (bartonella) •Clostridial infections •Zoonoses –erysipeloid,anthrax,tularemia Actinomycosis Causative organism: G+ anaerobic bacteria Actinomyces israelii Clinical types: CERVICOFACIAL ACTINOMYCOSIS the commonest form, initially a red indurated nodule on the cheek or submaxillary region. Multiple sinuses, scarring and the formation of new nodules produce an uneven lumpy surface. Fistulas or even small ulcerations arise. Characteristic sulphur granules may be found in the discharging pus. THORACIC ACTINOMYCOSIS and ABDOMINAL ACTINOMYCOSIS cause general symptoms such as fever, chills, night sweats and weight loss TH: PNC, lincomycin Erysipeloid •Causative agent: Erysipelothrix rhusiopathiae •persons who in their occupation handle infected fish, shellfish, poultry, or meat. •Three forms of this condition exist: •a mild localized form manifested by local swelling and redness of the skin; •a diffuse form that might present with fever; •and a rare systemic form associated with endocarditis •Th: PNC Anthrax • woolsorter's disease, •gram positive Bacillus Anthracis •exposure to infected animals or handling of hides or other animal products •Th: PNC, TTC Tularemia •Rabbit fever (rabits, hare,foxes..) • • •Francisella tularensis • • •Forms: ulceroglandular • mucosal • ocular • typhoid • •Th: macrolides • • • • • TEST TEST •What would you treat gonorhoea with? • a/ penicilin • b/ tetracycline • c/ PUVA • • •Mycosis fungoides originates from… • a/ T- lymphocytes • b/ B –lymphocytes • c/ NK cells • TEST •What causes pemphigus vulgaris? • a/ AB against desmosomes • b/ AB against hemidesmosomes • c/ AB against gluten • •Most biologicals used for the treatment of severe psoriasis are directed against… • a/ IL-12/23 • b/ IFN g • c/ TNF a • • TEST •The two main subtypes of atopic dermatitis are…. • a/ young and adult • b/ cutaneous and systemic • c/ extrinsic and intrinsic • •The cause of erysipelas is… • a/ Hemophilus Ducreyi • b/ b hemolytic Streptococcus • c/ Staphylococcus aureus •