Infectious diseases of the skin and wound

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Infectious diseases of the skin and wound

  1. 1. MAJID MOHIUDDIN
  2. 2.  VIRAL INFECTIONS:  Chickenpox and Shingles  German Measles, Rubella  Measles, Hard Measles, Rubeola  Smallpox  Warts BACTERIAL INFECTIONS:  Acne  Anthrax, Woolsorter’s Disease  Gas Gangrene, Myonecrosis  Leprosy, Hansen (or) Hansen’s Disease  Staphylococcal Skin Infections (Folliculitis, Furuncles, Carbuncles, Abscesses, Impetigo, Impetigo of Newborn, Scalded skin Syndrome)  Streptococcal Skin Infections (Scarlet fever, Erysipeles, Necrotizing Fascilitis) FUNGAL INFECTIONS:  Dermatophylosis, Tinea (Ringworm) infection, Dermatomycosis PROTOZOAL INFECTIONS:  Leishmaniasis
  3. 3.  Also known as Varicella. Acute, Generalized viral infection with fever mild constitutional symptoms & skin rash. Vesicles also forms in mucous membranes. Usually mild, self limiting disease but can be severely damaging to a fetus. Serious complications include pneumonia. Secondary infection (Bacterial):  Hemorrhagic complications & Encephalitis Raye (Rize) syndrome (severe encephalomylitis with liver damage)
  4. 4.  Also known as Harpes Zoster. Is a reactivation of Varicella Virus. Often result of immunosuppression Inflammation of Sensory ganglia of cutaneous sensory nerves, producing fluid filled blisters, pain and parasthesia (numbness & tingling) Shinglesmay occur in any age, but most common after age 50 years.
  5. 5. Etiologic/Causative AgentVaricella-Zoster Virus (VZV): Herpes Virus(Family Herpesviridae) also known as Herpesvirus3 Reservoirs--- A DNA VirusInfected Humans Mode of Transmission-Person to person by direct contact-Droplet (or) airborne spread of vesicle fluid-Secretions of the respiratory system of persons with Diagnosis chickenpox.-Clinical and epidemiologic grounds.-immunodiagnostic procedure are available.
  6. 6.  Mild, Febrile Viral disease. Fine, Pinkish, Flat rash begin 1 (or) 2 days after onset of symptoms. It starts on the face & neck & spreads to trunk arms & legs. Milder disease than hard measles with fewer complications. During pregnancy- may cause congenital rubella syndrome in fetus, this can lead to intrauterine death, spontaneous abortion (or) congenital malformations of major organ systems.
  7. 7. Etiologic/Causative AgentRubella Virus(Family Togaviridae)--- A RNA Virus ReservoirsInfected HumansMode of Transmission- By droplet spread- (or) direct contact with nasopharyngeal secretions of infected people. Diagnosis--immunodiagnostic procedure are available.
  8. 8.  An acute highly communicable viral disease with fever, conjunctivitis, cough, light sensitivity, koplik spots in mouth & red blotchy skin rash. Rash begins on the face on 3rd to 7th day & then becomes generalized. Complications include bronchitis, pneumonia, otitis media & encephalitis. Rarely autoimmune, subaceute, Sclerosing
  9. 9. Etiologic/Causative AgentMeasles (Rubeola) virus(Family Paramyxoviridae)--- A RNA Virus ReservoirsInfected HumansMode of Transmission- Airborne transmission by droplet spread- (or) direct contact with nasal (or) throat secretions of infected people.- With articles freshly soiled with nose & throat secretion. Diagnosis- Clinical & epidemiological grounds- immunodiagnostic procedure are available.
  10. 10.  A Systemic viral infection with fever, malaise (fatigue), headache, prostration, severe backache, characteristic skin rash, and occasional abdominal pain and vomiting. Rash is similar to rash of chickenpox. The disease can become severe, with bleeding into the skin and mucous membranes, followed by death. The World Health Organization (WHO) was able to eradicate smallpox via. A combination of isolation of infected persons and vaccination of others in the community.
  11. 11. Etiologic/Causative AgentTwo strains of variola virus; Variola Minor & Variola Major(Family Poxviridae) Reservoirs--- A DNA VirusInfected Humans was only source of the virus Mode of Transmission before.- Person to Person.- Patients are most contagious before eruption Diagnosis of the rash, by aerosol droplets from oropharyngeal lesions.
  12. 12.  Many varieties of skin and mucous membrane lesions including common warts ( Verrucae vulgaris), venereal warts, and Plantar warts. Most are harmless, but some can become cancerous.
  13. 13. Etiologic/Causative AgentAt least 70 different types of Human papillomaviruses- HPVGenus: Papillomavirus & (Family Papovaviridae) Reservoirs--- A DNA VirusInfected Humans Mode of Transmission- Direct contact.- Genital warts are sexually transmitted.- Easily spread from one area of the body to another. Diagnosis- Most are not very contagious from person to person.
  14. 14. A common condition in which pores become clogged with dried sebum, flaked skin and bacteria. Leads to the formation of blackheads and white heads (collectively known as acne pimples) and inflamed. Infectedabscesses: more common among teenagers.
  15. 15. Etiologic/Causative Agent- Propionibacterium acnes- Propionibacterium spp.- All are anaerobic Gram+ve bacilli. ReservoirsInfected HumansMode of Transmission- Probably not transmissible. Diagnosis- Clinical grounds.
  16. 16.  Anthrax can affect the skin (cutaneous anthrax). The lungs (Inhalation (or) Pulmonary anthrax).  GI tract (Gastrointestinal anthrax). Incutaneous anthrax depressed blackened lesion called ESCHARS occur. Inhalation & gastrointestinal anthrax are often fatal but
  17. 17. Etiologic/Causative Agent- Bacillus anthracis- A spore forming, G+ve bacillus. Reservoirs- Anthrax infected animals,- Spores may be present in soil, animal hair, wool, animal skins and hides and product made from them. Mode of Transmission- By entry of endospores through breaks in skin, inhalation of spores (o) ingestion of bacteria in Diagnosis contaminated meat.- Isolation from blood, lesions (or) discharges.- Identification using biochemical (or) enzyme based tests.
  18. 18.  Necrosis (Tissue death) due to ischemia (Lack of oxygen) is called gangrene. Gangrene may (or may not involve pathogens. However one type of gangrene, called Gas gangrene also called Myonecrosis always involved pathogens. Gas released from infected pathogens cause pockets of gas to
  19. 19. Etiologic/Causative Agent- Genus: Clostridium. Clostridium spp. (Clostridium perfringens)- Anaerobic bacteria.- Necrotizingenzymes and toxins produced in wounds. Reservoirs- Mode of Transmission Soil- Human become infected when soil containing clostridial spores enters an open wound. Diagnosis- G+ve (or) Gram variable bacilli in Gram stained smears of wound specimens.- Often no leukocytes are observed as they have been killed by toxins produced by the clostridia.- Once isolated on culture media, the spp. Can be determined using biochemical (or) enzyme based tests.
  20. 20.  LEPROMATOUS LEPROSY: Numerous nodules in skin; may be involvement of the nasal mucosa and eyes. TUBERCULOID LEPROSY: Few skin lesions; peripheral nerve involvement tends to be severe, with loss of sensations. HANSEN’S DISEASE is named for G.A. Hansen in 1873 discovered bacillus causes leprosy. Occur primarily in warm, wet areas
  21. 21. Etiologic/Causative Agent-Mycobacterium leprae : an acid fast bacillus Reservoirs- Infected Humans (nasal discharges & shed from cutaneous lesions) Mode of Transmission-Organism may gain entrance through respiratory system (or) broken skin.- It may be contagious if prolong close contact with an infected person. Diagnosis- Tuberculoid form of leprosy is not contagious.-M. leprae cannot be grown on artificial culture media.-Can be cultured only in laboratory animals.-Demonstration of acid fast bacilli in skin smears (or) skin biopsy specimens
  22. 22. (Folliculitis, Furuncle, Carbuncles, Abscesses, Impetigo, Impetigo of the new born, Scalded Skin Syndrome) All infected hair follicles, boils (furuncles), carbuncles and Stys – involve – Staphylococcus aureus. Majority common skin lesions are localized, discrete, uncomplicated. However, seeding of the blood stream may lead to pneumonia, lung abscess. IMPETIGO: occurs mainly in children, pus filled blisters (Pustules) may appear anywhere on the body. IMPETIGO OF NEWBORN: (Impetigo
  23. 23. Etiologic/Causative Agent-Staphylococcus aureus : G +ve-Impetigo may caused by G+ve (Streptococcus pyogenes)-S. Aureus spreads through skin by producing Hyaluronidase.-SSSS is produced by strains of S. aureus that produce expoliative(or epidermolytic) toxin, which causes the top layer of skin (epidermic) to split from the rest of the skin. Reservoirs- Infected Humans: Person with a draining lesion or any purulent discharge are the most common sources of epidermic spread. Mode of Transmission-Direct contact with a person having a purulent lesion (or) is an asymptomatic carrier.-In hospitals spread by hands of healthcare workers. Diagnosis-Isolation culture media & identify by biochemical (or) enzyme based tests. Susceptibility test must be performed because many strains of S.aures are multi drug resistant.
  24. 24. (Scarlet Fever, Erysipelas and Necrotizing Fasciilitis) STREPTOCOCCAL IMPETIGO: Usually superficial: may proceed through vesicular pustular and encrusted stages. SCARLET FEVER(SCARLATINA): wide spread pink red rash, most obvious on the abdomen, sides of the chest & in skin folds; severe cases may be accompanied by high fever, nausea and vomiting. ERYSIPELAS: an acute cellulitis with fever constitutional symptoms & hot, tender, red eruptions (sometimes referred to as St. ANTHONY’S FIRE) NECROTIZING FASCIITIS: caused by “Flesh eating bacteria”. Fasciitis is inflammation of the fascia (fibrous tissue) that envelops the body beneath the skin; also encloses
  25. 25. Etiologic/Causative Agent-Streptococcus pyogenes : G +ve coccus also known as group A beta hemolytic Streptococcus (GAS) and Strep A – Scarlet fever is caused by Erythrogenic toxin, produced by some strains of S.pyogenes.-It can be complication (sequela) of untreated strep throat (Streptococcal pharyngitis) Reservoirs- Mode ofHumans Infected Transmission-Person to Person via. Large respiratory droplets-Direct contact with patients (or) carriers.-Rarely by indirect contact through objects. Diagnosis-Isolation culture media & identify by biochemical (or) enzyme based tests. Immunodiagnostic procedures are available such as “Rapid strep tests”.
  26. 26.  The Dermatophytoses (Tinea infections (or) ringworm infections) are named in accordance with the site of infections fungal lesions of  The scalp (Tinea capitis)  Groin area (Tinea crusis) or (Jock Itch)  Trunk of the body (Tinea corporis)  Foot (Tinea pedis (or) Athlete’s foot). Some fungal infections cause only limited irritation scaling & redness. Other causes itching, swelling, blisters & severe scaling.
  27. 27. Etiologic/Causative Agent-Microsporum, Epidermaphyton & Trichophyton Spp. : Dermatophytes. Reservoirs- Mode ofHumans, Animals & Soil. Infected Transmission-Direct & indirect contact with lesions of infected humans (or) animals, contaminated floors, shower stalls, locker room benches, barber clippers, combs, hair brushes, clothings.- Spores enter through breaks in skin & moist area & Diagnosis germinate into filamentous growths.-Microscopic examination of potassium hydroxide (KOH) preparations of skin scrapings can reveal the presence of fungal hyphae.-Dermatophytes can culture of various media like sabarauds dextrose agar.
  28. 28.  Cutaneous, Mucosal and Visceral Leishmaniasis. The cutaneous form starts with a papule that enlarges into a crater like ulcer. Individual ulcers may coalesce.
  29. 29. Etiologic/Causative Agent-Various spp. Of flagellated protozoa – Genus : Leishmania.The motile, extracellular form is called a promastigote; The non motile, intracellular form is called an amastigote. Reservoirs-Infected Humans, domestic dogs, a variety of wild animals.-Leishmaniasis is principally a Zoonosis & usually Mode of Transmission of an infected sand fly. transmitted via. The bite Diagnosis-By Blood transfusion & person to person contact has been reported.-Microscopic identification of the amastigote form in stained preparations from aspirates & biopsies of ulcers; seen within macrophages & close to discrupted cells.-The promastigote form can be cultured on suitable media.
  30. 30.  When the protective skin barrier is broken as a result of burns, puncture wounds, surgical procedures (or) bites, opportunistic indigenous microflora and environmental bacteria can invade and cause local (or) deep tissue infections. The pathogens may spread via. Blood (or) lymph, causing serious systemic infections.

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