Week 8 - Dermatological System Flashcards
1
Q
Staph Aureus
A
- Aerobic
- Inhabits skin, throat, anterior nairs
- Cell wall has protein A (inhibit phagocytosis) - virulence factor
- Membrane damaging exotoxin
2
Q
Folliculitis/Furunculosis
A
- Inflammation of hair follicles
- Precipitated by chaffing, friction, heat
- Usually caused by staphylococcus
- Small red bumps/pimples around hair follicle can spread to non-healing crusty sores
- Tender/itching at site
3
Q
Pathogenies
A
Invade follicular wall causing infectious process
4
Q
Staphylococcal Scaled Skin Syndrome
A
- Less common staph infection
- Scarlet fever like rash
- Children under 5 most effected
- Deeper skin infection - superficial layers of epidermis separated & shed in sheets
- Caused by hematological spread of toxins
5
Q
Methicillin Resistant Staph Aureus MRSA
A
- Bacteria resistant to several antibiotics
- Can cause pneumonia, surgical site infections, sepsis, death - problem in hospitals/nursing home
- Spread by direct contact with infected wound & contaminated hand (healthcare worker)
- Some people carry MRSA, no signs of infection can spread to others
- Bacterial culture to diagnosis
6
Q
Group A Beta-Hemolytic Streptococci
A
- Skin & soft tissue infections
- Impetigo
- Cellulitis
- Erysipelas
- Necrotizing fasciitis (flesh eating disease)
7
Q
Strep
A
- Sphere chains
- Can be part of normal oral flora
- Don’t use oxygen, aerotolerant
- Complex nutrition requirements
- Capsule contains hyaluronic acid, fimbriae, exotoxins - virulence factors
8
Q
Impetigo
A
- Superficial bacterial infection
- Caused by strep group A or staph
- Common among infants/children
9
Q
Impetigo Progression
A
- Initially appears as small vesicle/pustule or large bulli on face
- Primary lesion ruptures leading denuded area discharges honey-colored serous liquid
- Liquid dries & hardens on skin surface leaving honey-colored crust
- New vesicles erupt within hours
- Accompanied by peritus - from scratching, multiplying infection site
10
Q
Erysipelas
A
- Superficial infection of upper skin layers
- Caused by strep group A
- Orange peel skin
11
Q
Erysipelas Progression
A
- Begins with minor trauma - burn, bruise, wound, incision
- First appears as localized lesion tender & red
- Lesion quickly develops bright red shiny color & spreading raised border
- Presence of lesion alone is typically diagnostic
- Accompanying headache, fever, chills, general illness
12
Q
Cellulitis
A
- Deeper infection affecting dermis & subcutaneous tissue
- Caused by group A strep could be staph
- Result of animal scratch/bite
- Expanding red swollen tender plaque lesion
13
Q
Measles (Rubeola)
A
- Caused by paramyxovirus - RNA
- Rash - macular & blotchy
- Macules can become confluent
14
Q
Measles Progression
A
- Begins on face, spreads to appendages
- Spread from child to child via direct contact with discharge from nose/throat airborne droplets
- Erythematous macules & papules spread from head down
15
Q
Measles Symptoms
A
- Fever
- Malaise
- Conjunctivitis
- Cough
- Coryza infectious complications
- Koplik spots in mouth
16
Q
Koplik
A
- Tiny bluish-white spots on erythematous base
- Cluster adjacent to molars on buccal mucosa
17
Q
Rubella
A
- Disease in childhood
- Caused by rubella virus - togavirus
- Diffuse punctate pinkish muscular rash
- Petechial lesions on soft palate (forsheimer’s sign)
18
Q
Rubella Progression
A
- Begins on trunk, spreads to arms/legs
- Spread from infected mother to fetus, secretions from infected person
- Contact can cause miscarriage
19
Q
Children with Congenital Rubella Syndrome
A
- Tetralogy of Fallot
- Ventricular septal defect
- Right ventricular outflow obstruction
- Pulmonic stenosis
- Overriding aorta
20
Q
Roseola Infantum (HHV 6)
A
- Children under 3 - peak 9 months
- Macropapular rash covering trunk & spreading to appendages
- Abrupt onset of high fever 40+ degrees
- Fever symptoms improve at same time rash appears
- Erythematous macules & papules surrounded by white halos
21
Q
Roseola Symptoms
A
- High fever 3 days
- Then rash
- Mild URI sx
- Febrile seizure complication - high body temp
22
Q
Erythema Infectiosum (Parvovirus B19)
A
- Common in childhood
- Spread via direct contact with discharge from nose/throat, infected blood, mother/fetus
- Moderately contagious prior to onset of rash
23
Q
Erythema Infectiosum (Parvovirus B19) Clinical Signs
A
- No high fever
- First bright erythematous rash on cheeks, forehead
- Circumoral pallor
- Rash can reappear with sunlight exposure, extreme temps, skin trauma
- Symmetric maculopapular lacy reticulated rash on trunk
24
Q
Varicella/Chicken Pox
A
- Varicella-zoster virus, form of herpesvirus
- Direct contact or through air transmission
- Contagious for 1-2 days before rash & until blisters scab
25
Varicella Progression
- 1st papule, then vesicle, then ulcer scabs over
- Papular stage - within hours papules develop on trunk, spread to limbs, buccal muscosa, scalp, axilla, upper resp tract, conjunctiva
- 2nd phase - papules form fluid-filled blisters
- 3rd phase - vesicles break open & scab
- Mild-extreme pruritus accompanies lesions - scratching, development of secondary infection
26
Varicella Complications
- Secondary bacterial infections
- Pneumonia
- Encephalitis
- Cerebellar ataxia
- Transverse myelitis
- Reye syndrome
- Death
27
Zoster (Shingles)
- Acute localized vesicular eruption on skin
- Caused by same herpes as chickenpox
- Result of reactivation of latent chickenpox infection that has been dormant in sensory dorsal root ganglia since primary infection
28
Zoster Progression
- Age-related decline of varicella zoster T-cell mediated immunity, increased viral activation of older age group
- Reactivated virus travels from ganglia in skin of corresponding dermatome
- Virus only contagious to those not immune to chicken pox
- When transmitted to non-immune individual causes chicken pox
29
Zoster Lesions
- Preceded by prodrome consisting of burning & tingling sensation
- Extreme sensitivity of skin to touch
- Pruritus along affected dermatome
- Prodromal symptoms may be present 1-3 days prior to rash appearance
- Lesions appear as eruption of vesicles with erythematous base
- Restricted to skin areas supplied by sensory neurons of single group of dorsal root ganglia
30
Zoster Complications
- Permanent blindness - eye involvement
- Postherpetic neuralgia - pain persists 1-3 months after rash resolution
31
Hand, Foot & Mouth Disease (coxsackievirus A5)
- Common infection in children under 5
- Caused by coxsackievirus
- Sores/ulcers inside or around mouth
- Rash/blisters on feet, legs, hands, butt
- Can be extremely painful
- Not serious infection
32
Hand, Foot & Mouth Disease Symptoms
- Fever
- Sore throat
- Resp & GI sx
33
Yeasts
- Grow as single cells
- Reproduce asexually
34
Molds
Grow in hyphae filaments
35
Superficial Infection of Skin
- Ringworm
- Invade superficial skin, hair, nails
- Fungi live on dead cells of epidermis
- Emit enzyme enabling keratin digestion
- Microscopic exam of skin scraping
36
Deep Infections of Skin
Involve epidermis, dermis & subcutaneous tissue
37
Potassium Hydroxide Prep
- Used to prepared slides of skin scrapings
- KOH disintegrates human tissue leaving behind hyphae
38
Dermatophyte Infections
- Tinea capitis - scalp
- Tinea corporis (ringworm)
- Tinea pedis - feet
- Tinea unguium - nails
39
Trichophyton Rubin
Most common causative agent of tinea
40
Ringworm
- Well defined red boarder
- Central scaling
41
Tinea Capitis
Partial alopecia - hair breakage
42
Tinea Unguium
- Difficult to get rid of
- Long-term antifungal - 50% reduction/resolution
- Recurrence common
43
Candida Albicans
- Native to GI tract
- Thrives on warm, moist skin folds
- Red rash with defined boarders
- Patches erode epidermis
- Can be scaling
- Mild-severe itching & burning
- Severe = pustules
44
Candida Albicans Risk Factors
- Diabetes
- Previous antibiotics
- Pregnancy
- Oral Contraceptives
- Poor nutrition
- Immunocomp
