Dr.Ahmed Abdul-Aziz Ahmed Assistant Clinical Professor Dermatology&Venerology. F.I.B.M.S.
1.Bacterial Skin infction 2.Acne &Rosacea 3.Urticaria &Angioedema&Erythemas 4.GenodermatosisBacterial Skin Infection
WWW.SMSO.NETBasic structure of infectious agents
VIRUSES BACTERIA FUNGI PROTOZOA HELMINTHS Cell structure Not applicable Prokaryotic Eukaryotic Eukaryotic Eukaryotic Size + + + +++ ++++ +++++ DNA and RNA No Yes Yes Yes Yes Living? No Yes Yes Yes Yes Nucleus? Not applicable No Yes Yes Yes Ribosomes Not applicable 70S 80S 80S 80S Internal organelles Not applicable No Yes Yes Yes Multicellular? Not applicable No Both No Yes Cell wal l Not applicable Yes,peptidoglycan Yes, chitin No No
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Major families of bacteriaWWW.SMSO.NET
Major families of bacteriaWWW.SMSO.NET
Pathogenesis
Primary Infections Usually affect normal skin, entering through a break in the skin such as an insect bite. Characteristic clinical picture and disease course Caused by a single pathogen Many systemic infections involve the skin Secondary Infections: Infection of skin that is already diseased. Variable clinical picture because of the underlying disease
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Medstat.med* Impetigo Contagiosa
* Impetigo ContagiosaImpetigo on an uncommon site showing erosions, crusting and rupture blisters.
* Impetigo Contagiosa* Bullous Impetigo
* Bullous Impetigo
WWW.SMSO.NETBullous Impetigo
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Impetigo contagiosaImpetigo
Circinate impetigo: with peripheral extension of lesion & healing in the center.
Varities:Crusted impetigo: on the scalp complicating pediculosis. Occipital & cervical LNs are usually enlarged & tender.
Age: all ages, but commoner in childhood & newborn (impetigo neonatorum). Site: face is often affected, but the lesions may occur anywhere, including palms & soles.
Bullous Impetigo
The bullae are less rapidly ruptured (persist for 2-3 days) & become much larger. The contents are at first clear, later cloudy. After rupture, thin, brownish crusts are formed.
Ecthyma (ulcerative impetigo): adherent crusts, beneath which purulent irregular ulcers occur. Healing occurs after few wks, with scarring.
* Ecthyma
WWW.SMSO.NETEcthyma
Staphylococcal scalded skin syndrome in a child. The overlying epidermis is loosening in the red areas
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Staphylococcal scalded skin syndromeExfoliatin (epidermolysin) split off the upper part of the epidermis just beneath the granular cell layer. The inciting infection may be on the skin but usually is in the eye or nasopharynx. The toxin enters the circulation and affects the skin systemically, as in scarlet fever.Nikolosky’s sign
* Staphylococcal Scalded Skin Syndrome
* Staphylococcal Scalded Skin Syndrome
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SSSS and TENFOLLICULITIS
WWW.SMSO.NETFolliculitis
Fc
a dome-shaped pustule at the orifice of a hair follicle that heals within 7-10 days.
Superficial Folliculitis (Bockhart’s Impetigo)from penetration into the skin of sharp tips of shaved hairs.
pseudofolliculitisIt is a staphylococcal infection similar to, but deeper than folliculitis & invades the deep parts of the hair folliculitis. Occasionally several closely grouped boils will combine to form a carbuncle. The carbuncle usually occurs in diabetic cases. The site of election is the back of the neck.
Frunculosis (boils)
* Furuncle
* Furuncle / CarbuncleWWW.SMSO.NET
Boils. FurunclesBs
)
Carbuncle
CELLULITIS & ERYSIPELAS
Cellulitis
WWW.SMSO.NETCellulitis
Limbs Redness. Swelling Increased warmth Tenderness Blistering Regional lymphadenopathy Abscess
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CellulitisWWW.SMSO.NET
ErysipelasWell-defined, raised border and marked swellingf affected skin.
Erysipelas note sharp spreading edge, here demarcated with a ballpoint pen.
* Erysipelas
* Cellulitis
* CellulitisErythema, heat, swelling and pain or tenderness. Fever and malaise which is more severe in erysipelas. In erysipelas: blistering and hemorrhage. Lymphangitis and lymphadenopathy are frequent.
Edge of the lesion: well demarcated and raised in erysipelas and diffuse in cellulitis.
SKIN DISEASES RELATED TO CORYNEFORM BACTERIAErythrasma
It is mild, chronic, localized superficial infection of skin by Coryn. Minutissimum. Clinically: sharply-defined but irregular brown, scaly patches
Pitted keratolysis of the heel
Pitted keratolysis of the heel
usually localized to groins, axillae, toe clefts or may cover extensive areas of trunk & limbs. Obesity & DM may coexist.Coral red fluorescence under wood’s light.
* Intertrigo
Presentation: Superficial inflammatory dermatitis where two skin surfaces are in apposition. Etiology: Friction and moisture allows infection by bacteria (Staph, Strep, Pseudo.) or fungi or both.* Intertrigo
* Intertrigo* Intertrigo
* Pyogenic ParonychiaPresentation: Tender painful swelling involving the skin surrounding the fingernail. Etiology: Moisture induced separation of eponychium from nail plate by trauma or moisture leading to secondary infection. Often work related Bacteria cause acute abscess formation, Candida causes chronic swelling. Treatment: Avoid maceration / trauma I&D of abscess PCN, 1st Gen Cephalosporin, augmentin. Chronic infection requires fungicide and a bactericide.
* Pyogenic Paronychia