Chapter 19 - Skin Flashcards
Layers of the epidermis, bottom up.
- Stratum basalis (stem cell)
- Statum spinosum (desmosomes!)
- Stratum granulosum
- Stratum corneum
What type of immune response is Eczema? What is it associated with?
Type I. Associated with asthma and allergic rhinitis.
What type of bacteria causes acne?
Propionibacterium acnes
Acanthosis = ?
Epidermal hyperplasia
Parakeratosis =
Kyperkeratosis with retention of keratinocyte nuclei in stratum corneum.
Histology findings with Psoriasis? (4)
- Acanthosis
- Parakeratosis
- Munro microabscesses (collection of neutrophils in the stratum corneum)
- Auspitz sign (bleeding when scale picked off).
5 P’s of Lichen Planus?
Pruritic, planar, polygonal, purple papules.
Histological appearance of Lichen Planus?
‘Saw-tooth’ appearance.
what is Lichen Planus associated with?
Chronic Hep C infection.
Presentation of Pemphigus Vulgaris and target of autoimmune destruction?
Presents as skin and oral mucosa bullae, positive Nikolsky sign. Due to autoimmune destruction of DESMOSOMES.
Presentation of Bullous Pemphigoid and target of autoimmune destruction?
Presents as skin bullae ONLY (no mucosal involvement), negative Nikolsky sign. Due to autoimmune destruction of hemidesmosomes. More mild than Pemphigus vulgaris.
What is Dermatitis Herpetiformis and what is it associated with?
Autoimmune deposition of IgA at the tips of dermal papillae, presents as pruritic vesicles that are herpetiform (grouped).
Strong associated with CELIAC DISEASE.
What is Erythema Multiforme associated with?
HSV infections, Mycoplasma, drugs (penicillin and sulfonamides), autoimmune disease (SLE), and malignancy.
Waxy, ‘stuck on’ appearance, with keratin pseudocysts ???
Seborrheic Keratosis
What is Leser-Trélat sign?
The sudden onset of multiple seborrheic keratosis. Indicates underlying carcinoma (GI)
What is Acanthosis Nicricans and what is it associated with?
Epidermal hyperplasia with darkening of the skin. Associated with insulin resistance and malignance (esp. gastric carcinoma).
What type of skin cancer appears on the upper lip?
Basal Cell Carcinoma
Histology of Basal cell carcinoma?
Nodules of basal cells with peripheral palisading.
Keratin pearls = ???
Squamous Cell Carcinoma.
What type of skin cancer appears on the lower lip?
Squamous Cell Carcinoma.
What is a precursor of Squamous Cell Carcinoma?
Actinic Keratosis
What is a keratoacanthoma?
Well differentiated squamous cell carcinoma that develops rapidly and regresses spontaneously. Presents as a cup shaped tumor filled with keratin debris.
What cell type do melanocytes derive from?
Neural Crest Cells
Where is melanin made and what is the precursor molecule?
Made in melanosomes using tyrosine.
Cause of Vitiligo?
Autoimmune destruction of melanocytes.
Common cause of Albinism?
Enzyme defect (usually tyrosinase) that impairs melanin production.
What causes freckles (ephelis)?
Increased number of melanosomes, NOT melanocytes.
ABCDE’s of melanoma?
Asymmetry Border irregular Color not uniform Diameter >6mm Evolution
Most important factor for predicting metastasis in melanoma?
Depth
Common bacterial cause of impetigo?
Staph aureus OR Staph pyogenes
Common bacterial cause of cellulitis?
Staph aureus OR Staph pyogenes.
What cellular component causes Staphylococcal Scalded Skin Syndrome?
Exfoliative A and B toxins lead to epidermolysis of stratum granulosum… (Staph aureus)
What do firm, pink, umbilicated papules indicate (most often in children…)
Mulluscum Contagiosum (due to POXVIRUS)
