Dermatology Flashcards
Layers of epidermis
From surface to base:
- stratum corneum (keratin-containing)
- stratum lucidum
- stratum granulosum
- stratum spinosum (desmosome containing)
- stratum basale (stem cell site)
Zonula occludens
Tight junctions of skin. Prevent paracellular movement of solutes. Made of claudins and occludens. Most superficial connection of skin cells.
Zonula adherens
Adherens junctions of skin. Cadherins connect actin cytoskeletons of adjacent cells. Deep to tight junction; superficial to desmosomes.
Macula adherens
Desmosomes. Provide support by keratin interactions. Autoantibodies develop against them in pemphigus vulgaris.
Gap junctions
Deepest cell-cell junction in skin. Connexons allow for electric and chemical communication between cells.
Hemidesmosome
Connects keratin in basal cells to underyling basement membrane. Autoantibodies against them in bullous pemphigoid.
Spongiosis
epidermal accumulation of edematous fluid in intercellular spaces
Acantholysis
Separation of epidermal cells
Acanthosis
Epidermal hyperplasia
Albinism
Normal melanocyte number; decreased melanin production due to decreased tyrosinase activity or defective tyrosine transport. Also can be caused by failed nueral crest migration during development
Melasma
Hyperpigmentation associated iwth pregnancy or OCP use
Vitiligo
Irregular areas of depigmentation due to autoimmune destruction of melanocytes
Atopic dermatitis
Same thing as eczema. Prurutic eruption on skin flexures. Starts on face in infancy; appears in antecubital fossae later
Allergic contact dermatitis
Type IV hypersensitivity
Melanocytic nevus
Regular mole. Intradermal are papular; junctional are flat
Psoriasis
Papules and plaques with silvery scale. Acanthosis (epidermal hyperplasia) wither parakeratotic scaling (nuclei still in stratum corneum). Increased stratum spinosum; decreased stratum granulosum.
Auspitz sign
Pinpoint bleeding spots from exposure of dermal papillae when scales scraped off seen in psoriasis.
Rosacea
Inflammatory skin disorder with erythematous papules and pustules.
Seborrheic keratosis
Flat, greasy, pigmented squamous epithelial proliferation. Look stuck on. Occur on head, trunk, extremities.
Leser-Trelat sign
sudden apperance of multiple seborrheic keratoses; suggests underlying malignancy
Impetigo
Superficial skin infection caused by S aureus or S pyogenes. Honey colored crusting. S aureus can cause bullae as well.
Cellulitis
Infection of dermis and SC tissue. Usually S pyogenes or S aureus.
Erysipelas
Inferction of upper dermis and superficial lymphatics. Usually strep pyogenes. Well-defined demarcation between infected and normal skin
Abscess
Pus walled off within skin. Almost alwyas S aureus
Necrotizing fasciitis
Deep tissue injury from anaerobes or S pyogenes. Causes crepitus. Bullae and purplish color to skin
Staph scalded skin syndrome
Exotoxin destroys keratinocyte attachments in stratum granulosum. Fever, rash, skin sloughing
Molloscum contagiosum
Papules caused by poxvirus (dsDNA, replicates in cytoplasm)
Hairy leukoplakia
Irregular, white, painless plaques on tongue that can’t be scraped off. Caused by EBV in immunocompromised patients.
Pemphigus vulgaris
Potentially fatal. IgG against desmoglein in desmosomes. Flaccid intraepidermal bullae. Oral mucosa involved. Separation of epidermis on manual stroking of skin. Net-like apattern on IF.
Bullous pemphigoid
IgG against hemidesmosomes. Tense blisters containing eosinophils on skin. Oral mucosa spared. Linear pattern on IF.
Dermatitis herpetiformis
Pruritic papules, vesicles, bullae due to IgA deposits at tips of dermal papillae. Associatd with celica
Erythema multiforme
Associated with infections, drugs, cancer, and autoimmune disease. Multiple types of lesions
Stevens Johnson syndrome
Fever, bullae and necrosis, skin sloughing. High mortality rate. Adverse drug reaction
Acanthosis nigricans
Epidermal hyperplasia causing hyperpigmented thickening of skin in axilla or neck. Associated with high insulin and visceral malignancies
Actinic keratosis
Premalignant lesions caused by sun exposure. Small, rough, red or brown papules or plaques.
Erythema nodosum
Painful inflammatory lesions of subcutaneous fat on anterior shins
Lichen planus
Associated with hep C. Pruritic purple polygonal palmar papules and plaques. Wickham strae if mucosal involvement- reticular white lines.
Pityriasis rosea
Patch followed by other scaly erythematous plaques in christmas ree distriution. Self-resolves in 6-8 weeks
Basal cell carcinoma
Pink pearly nodules. Often with telangiectasias, rolled borders, central crusting or ulceration. Palisading nuclei
Squamous cell carcinoma
Associated with immunosuppression. Face, lower lip, ears, and hands are most common spot. Ulcerative red lesions with frequent scale. Keratin pearls on histology. Actinic keratosis is precursor lesion.
Melanoma
S-100 tumor marker. Depth of tumor correlates with risk of metastasis.
Types: superficial spreading, nodular, lentigo maligna, acral lentiginous
BRAF mutations common
Types of bruises
Petechiae: pinpoint to pinhead (less than 5mm) bruises
Purpora: 5mm to 1 cm
Ecchymoses: over 1cm
TGF beta
Stimulates connective tissue synthesis and remodeling of ECM. Persistently elevated in formation of keloid scars
Ehlers-Danlos syndrome
Can be caused by procollagen peptidase deficiency, reuslting in impaired cleavage of terminal propeptides in ECM.
Response to foreign body in a wound
Granulation tissue
