Yellow causative agent Green symptoms unique to disease Light Blue toxins virulence factors Purple vaccine Violet specific medicine Skin Infections Streptoococcal Impedigo Causative agent o Streptococcus pyogenes o Staphylococcus aureus Signs and Symptoms crusts of drying plasma o Little fever or pain o Enlarged lymph nodes Pathogenesis Most common type of pyoderma characterized by pus production resulting from infection of insect bite burn scrape etc o Superficial skin infection with inflammation o Thin walled blisters develop and break replaced by oozing yellowish o Many strains of S pyogenes some colonize the skin o Minor injuries introduce into deeper layer of epidermis o Hyaluronic acid capsule and M protein of cell wall interfere with phagocytosis o Virulence factors o Streptococcal products absorbed into circulation can yield immune proteases nucleases hyaluronidase response produce post streptococcal sequelae including acute glomerulonephritis Epidemiology o Common among poor children in hot humid areas o Person to person contact insects fomites o Throat and nasal carriers Treatment and Prevention o Penicillin or erythromycin o Wound cleaning antiseptics avoiding contact o Keep skin clean avoid sharing personal items Hair follicle infections Folliculitis Small red bump or pimple o If hair pulled infection resolves o Infection can spread to adjacent tissues resulting in furuncle or boil localized redness swelling tenderness Furuncles boils Pus often drains from lesion with a plug of dead tissue or inflammatory cells Cluster of furuncles carbuncle Shed large number of S aureus Should not work with food or patients Carbuncles Large areas of redness swelling tenderness with fever Numerous sites of draining pus Develop where skin is thick Staph Skin Infections Causative agent Diagnostic o Coagulase o Mainly Staphylococcus aureus o Spreading to subcutaneous tissue o Systemic spread can lead to infection of the heart brain bones o A significant pathogen responsible for numerous medical conditions o S aureus vs other staff clumping factor coagulase Not an enzyme Activates prothrombin thrombin Thrombin converts fibrinogen fibrin blood clot webs o Clumping factor Similar functionally to coagulase Attaches S aureus to fibrinogen and fibrin in wounds Plastic devices become quickly coated Staph Scalded Skin Syndrome SSSS Skin appears burned Primary in infants Potentially fatal Causative agent o S aureus o Disease due to production of exfoliatin made by 5 of strains o Toxin destroys outer layers of epidermis Symptoms o 1st generalized redness o Nose mouth genitalia may be painful first o 48hrs skin is red wrinkled large blisters tender Pathogenesis o Exfoliatin toxin is released even in small infections o Spreads to larger areas o Toxin splits the skin below dead keratinized outer layer o Outer layer peels o Susceptible tosecondary infectinos o Mortality rates 40 Epidemiology o Infants elderly immunocompromised o Person to person o Small epidemics can occur in nurseries Prevention Treatment o Protective patient isolation o Penicillinase resistant penicillin methicillin o Remove dead skin to prevent secondary infection Lyme Disease Causative agent o Borrelia burgdorferi Gram o Zoonosis Symptoms o First stage Erythema migrans skin rash that looks like a bull s eye Swollen lymph nodes o Second stage 2 8 weeks later Heart and nervous system Electrical conduction in heart impaired dizziness Paralysis of facial muscles severe headache impaired nerves o Third Stage Arthritis Large joints 6 months after rash Chronic nervous system impairment may occur Localized pain depression Epidemiology o Widespread in USA o Black legged tick Prevention Treatment o Check for ticks o Antibiotics relatively effective in early stage o Less effective in late disease Viral Skin Diseases Chicken Pox varicella Incidence decline due to vaccination Produces a latent infection Reactivated disease shingles Causative Agent o Varicella zoster virus o VSV Herpes virus family Medium sized enveloped virus Symptoms o Most cases mild recovery uncomplicated o Rash on back of head face mouth o Rash is diagnostic o Lesion progress red spots macules small bumps papules small blisters vesicles pus filled blisters pustules o Lesions itch and appear at different times o Healing begin after pustules break and crust over o Major threat to newborn Can lead to congenital varicella syndrome if mother develops disease in few days before and after birth High mortality severe birth defects o Sequellae complications Shingles herpes zoster Reactivation of dormant virus Rash around waist Reye s Syndrome Vomiting and coma Children 5 15 30 mortality Aspirin therapy increases risk Liver and brain damage Epidemiology o Annual incidence several million at one time o Decline due to vaccine o Transmitted by respiratory secretions and skin lesions o Incubation 2 weeks infective 1 2 days before rash and until blisters crust o Persist in the body Prevention and Treatment o Attenuated vaccine 1995 o Not during pregnancy or 3 months prior to pregnancy o Not for immune compromised patients o Shingles vaccine for 60 Measles Rubeola Hard measles and red measles Causative Agent o Rubeola virus o Pleomorphic enveloped Symptoms o Fever runny nose cough red weepy eyes o Fine rash on forehead that spreads to rest of body o Virus suppresses cell mediated immunity many secondary infections subacute sclerosing panencephalitis slow brain degeneration Pathogenesis o Respiratory route o Infected mucous membranes o Membranes covered in Koplik spots white spots in back of throat opposite molars Epidemiology o 750 000 children year die of measles o Leading cause of death among impoverished Prevention and Treatment o Vaccination in MMR vaccine mumps and rubella German Measles Common name for Rubella Mild Often unrecognized Causative Agent Significant concern in pregnant women o Rubella virus enveloped ssRNA o Togavirus o Congenital Rubella Syndrome In early pregnancy it easily passes through placenta and infects fetus Symptoms o Slight fever o Swollen lymphs o Facial rash of pink spots o Joint pain Epidemiology o Humans only natural host o 40 of infected people develop no symptoms but can spread virus o Infectious week before and week after Prevention and Treatment o Attenuated rubella virus vaccine o 12 month and booster at 4 6 o Pregnant women not vaccinated do to potential complications Wound infections Staphylococcal Leading cause of wound infection S aureus S