Skin Infections Flashcards
What are the layers of the skin?
Epidermis (stratum corneum)
Dermis
Subcutaneous Layer
Stratum corneum
25 cells thick, dead cells that have migrated from deeper layers
how often does the entire epidermis replace itself?
every 25-45 days
keratin
give cells the ability to withstand damage, abrasion, and water
Stratum Basale
several layers below the stratum corneum, attached to the dermis, source of cells that make up epidermis
What are the other protective characteristics of the skin?
sebaceous glands
antimicrobial peptides
sweat
lysozyme
What are the characteristics of the normal biota of the skin?
must be capable of living in dry and slaty conditions
majority of the normal biota are not culturable
What genera are found on the skin according to the Human Microbiome Project (HMP)
Streptococcus Staphylococcus Propionibacterium Corynebacterium Malassezia Pseudomonas Janthinobacterium
What are the maculopapular rash diseases?
characterized by flat to slightly raised colored bumps: measles rubella fifth disease roseola scarlet fever
What are other skin diseases that are not maculopapular rash diseases?
impetigo
cellulitis
SSSS
Rocky Mountain Spotted Fever
What are the vessicular or pustular rash diseases?
Chicken pox, small pox, HSV, warts, mycoses
Fifth disease
B19 parvovirus
Roseola
human herpes viruses
Impetigo
bacterial infection of skin common in children- usually near nose/mouth
Cellulitis
infected dermis connective tissue and subcutaneous layer
What is the common name for measles?
rubeola
Why was there a massive reduction in measles cases within the twentieth century?
Vaccination program
How do the symptoms of the measles start?
Fever, runny nose, cough and red weepy eyes
What appears within a few days of contracting measles?
fine rash: appears first on forehead then spreads to the rest of the body
When do measles symptoms generally disappear?
within a week
What are common and less common secondary infections you can get from measles?
common: pneumonia and earaches
Less common: encephalitis and subacute sclerosing panechalitis (SSPE: chronic progressive encephalitis)
What is the causative agent of measles?
rubeola virus
What are the characteristics of the rubeola virus?
pleomorphic, medium sized enveloped
Single stranded RNA genome
Belongs to paramyxovirus family
What are the virulence factors of the rubeola virus?
contains spike proteins, one for viral attachment to host, one for fusion with host membrane
What is the pathogenesis of measles?
infection via respiratory route» virus replicated in epithelium of upper respiratory tract» spreads to lymph nodes then spreads to the rest of the body
What is an important diagnostic sign of having measles?
infected mucous membranes
What is the epidemiology of measles?
humans are only natural host
virus spread by respiratory droplets
How many of the population was infected before routine immunization of measles?
over 99% of the population