Epidermis/Dermis Layers Flashcards
Most common agents in Tinea pedis
- Trichophyton mentagrophytes
- Trichophyton rubrum
- Epidermophyton floccosum
Most common agent in Tinea manuum
- Trichophyton rubrum
- Trichophyton mentagrophytes
- Epidermophyton floccosum
nails lose luster, become opaque/white, brittle, and have a crumbling consistency - commonly caused by?
White Superficial Onychomycosis (Leukonychia mycotica) is commonly caused by T. rubrum and T. metagrophytes
Most common agent in Tinea cruris
- Epidermophyton floccosum
- Trichophyton mentagrophytes
- Trichophyton rubrum
Most common agent in Tinea unguium
T. rubrum and T. metagrophytes
Most common fungal nail infection; nail thickens and often discolors
Distal Subungual Onychomycosis
Most common fungal nail infection in HIV pts; begins in nail fold
Proximal Subungual Onychomycosis
Nails hardened, thickened, brownish-green discoloration, w/ striated ridges or grooves; generally w/ cuticle involvement w/ or w/o pus
Paronychial or Onychomycotic Candidosis: AKA onychomycosis caused by Candida albicans
“weeping” or “scaled skin” lesion
Intertriginous Candidosis
Nonspecific febrile illness followed by rash w/ “slapped cheek” appearance
Erythema Infectiosum/Fifth Disease caused by HPV B19
HPV B19 - describe the genome and virus
ssDNA, non-enveloped virus w/ 1 serotype
socks and gloves maculopapular rash
Erythema Infectiosum/Fifth Disease caused by HPV B19
bone marrow biopsy reveals: presence of large pink or lilac colored inclusions in giant pronormoblasts
HPV B19 infection
HHV-6 uses __________ as a cellular receptor
CD46 - found on ALL human nucleated cells
Measles virus - describe the genome and virus
ssRNA, enveloped w/ 1 serotype
Which virus causes Giant cell formation
Measles virus
Complication of HPV B19
Aplastic Crisis
Rash and Fever
Measles
Measles rash is due to
immune system - T cell (HLA I and II on endothelial cells)
Describe a “Morbilliform rash” and what disease it exists with
symmetrical, non-pruritic, bright red maculopapular rash; Measles
Describe the rash appearance and disappearance with Measles
Begins on face and descends, ~1-2days later rash rapidly fades from top to bottom by fine briny desquamation
Giant Cell Pneumonia
Measles
Describe the genome and virus of VZV
Alpha herpesvirus: large, dsDNA virus, enveloped, encodes its own thymidine kinase w/ 1 serotype
VZV travels down nerves via
reverse axoplasmic flow
Primary infection with VZV, viral replication occurs
URT -> lymph nodes -> lymphoid tissue, liver, spleen, etc
Exfoliatin exotoxin mechanism
glutamate specific serine proteases highly specific to the cadherin desmoglein I
Exfoliatin exotoxin is produced by
Staph aureus
Exfoliatin exotoxin may cause
Bullous impetigo, SSSS, Ritter’s disease
dsDNA virus that replicates in the nucleus
Herpes
dsDNA virus that replicates in the cytoplasm
Variola major (Orthopox)
Candida pathogenic form
yeast, pseudohyphae, and hyphae
Risk Factors for Cutaneous Candidiasis
Female, young/old, diabetes, obesity (skin folds), pregnancy
Intertriginous Candidosis lesions
“weeping” or “scaled skin - Pruritic, erythematous w/ macerated edges
Paronychial or Onychomycotic Candidosis lesions
Chronic - Nails hardened, thickened, brownish-green discoloration, w/ striated ridges or grooves
Culture Candida on?
Sabouraud-Glucose agar
Definitive diagnosis for Candida?
Germ Tube Test
Cutaneous Candidosis Treatment
1% Crystal Violet
Paronychial Candidosis Treatment
Nystatin, Amphotericin B, Ketoconazole
HPV B19 has a predilection for
bone marrow and erythrocyte precursors
Is HPV B19 present in the rash?
No - immune-mediated
Biphasic course of HPV B19 is
-initial phase/prodrome caused by viremia at day8
FEVER BREAKS…
- Immune-mediated Rash (face->limbs/trunk->palms/soles)
Rash of Erythema Infectiosum is due to
Type III HSN rxn
Prodrome of Erythema Infectiosum begins on Day __ and lasts _____
Day 8 and lasts 2-3 days
Describe the course of the rash with Erythema Infectiosum
FEVER BREAKS….initially on the face as “slapped cheek” appearance w/ relative circumoral (around the mouth) sparing. Maculopapular rash may appear later on limbs, trunk, palms and soles (socks and gloves)… lasts 2-3 days
Does anything make the rash of Erythema Infectiosum worse?
exacerbated by exercise, emotion, hot baths, sunlight
Typical pt w/ Erythema Infectiosum
Late winter, early spring, endemic in 4-15 y/o, school or daycare outbreak
Erythema Infectiosum In Seronegative Adults causes
Prodrome: flu-like symptoms lasting 3-4 days
symmetric polyarthralgia of the hands and wrists, occasionally ankles and knees for 2-3 weeks
Erythema Infectiosum exposure in Pregnant female…
Treat w/ IVIG to prevent abortion
Complication of Erythema Infectiosum
Aplastic crisis (esp in anemic pts) for 7-10d
Immunity in Erythema Infectiosum
Humoral - Type III HSN
For Erythema Infectiosum, Bone marrow biopsy would reveal
large pink or lilac colored inclusions in giant pronormoblasts and absence of erythroid progenitor cells
Treatment for Erythema Infectiosum
Supportive – antipyretics, analgesics, NSAIDs
IVIG for immunocompromised/pregnant females
How does HHV-6 enter cells?
uses CD46 as a cellular receptor, glycoprotein expressed on the surface of all human nucleated cells
Clinically important serotype of HHV in Exanthem Subitum?
HHV-6B
HHV-6 - Life-long, active infection in
Salivary glands
HHV-6 - Persistent, latent infection in
macrophages and monocytes
Exanthem Subitum is biphasic, describe
Initial prodrome w/ HIGH fever
FEVER BREAKS…
Immune-mediated rash
Typical Patient w/ Exanthem Subitum
6mo - 3yrs
The prodrome of Exanthem Subitum begins ____ and lasts _____
4-7 days after exposure; lasts 4-6 days; characterized by HIGH fever
Exanthem Subitum Sx In Adults
Mononucleosis-like Sx: Fever, pharyngitis, cervical lymphadenopathy
Diagnosis of Exanthem Subitum
EIA IgM, but it cross-reacts w/ CMV
Treatment for Exanthem Subitum
Supportive
Measles virus initially replicates in
URT and draining lymph nodes
Measles in primarily controlled by what type of immunity
CMI
Is the rash of Measles infectious?
Yes
How does Measles cause malnutrition?
Desquamation of epithelium - GIT -> bloody diarrhea
Communicability of Measles?
Begins at prodrome and lasts until 4-5 after rash onset
Typical patient with Measles?
Winter/spring, nonvaccinated, 5-9
INcubation period of Measles
10-12 days
Prodromal Sx of Measles
High fever, coryza, conjunctivitis, brassy cough, cervical LAD, Koplik spots (secondary viremia)
Describe the rash of Measles
Fever and prodrome continue w/ rash appearance
“Morbilliform rash” symmetrical, non-pruritic, bright red maculopapular rash on face, confluent and descends to LE
Measles Rash clears by
desquamation from head –> toe
Atypical Measles patient population
people vaccinated b/w 1963-1967 w/ killed vaccine - vesicular and purpuric and starts on limbs
Complications of Measles
Otitis Media, Primary Viral Giant Cell Pneumonia, Diarrhea, encephalitis, Subacute Sclerosing Panencephalitis
Subacute Sclerosing Panencephalitis is caused by
defective measles virus
Subacute Sclerosing Panencephalitis is a condition where
fatal, slowly progressive, inflammatory, demyelinating disease of the CNS