Flashcards in Dermatology Deck (45):
Layers of epidermis
From surface to base:
-stratum corneum (keratin-containing)
-stratum spinosum (desmosome containing)
-stratum basale (stem cell site)
Tight junctions of skin. Prevent paracellular movement of solutes. Made of claudins and occludens. Most superficial connection of skin cells.
Adherens junctions of skin. Cadherins connect actin cytoskeletons of adjacent cells. Deep to tight junction; superficial to desmosomes.
Desmosomes. Provide support by keratin interactions. Autoantibodies develop against them in pemphigus vulgaris.
Deepest cell-cell junction in skin. Connexons allow for electric and chemical communication between cells.
Connects keratin in basal cells to underyling basement membrane. Autoantibodies against them in bullous pemphigoid.
epidermal accumulation of edematous fluid in intercellular spaces
Separation of epidermal cells
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
Hyperpigmentation associated iwth pregnancy or OCP use
Irregular areas of depigmentation due to autoimmune destruction of melanocytes
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
Regular mole. Intradermal are papular; junctional are flat
Papules and plaques with silvery scale. Acanthosis (epidermal hyperplasia) wither parakeratotic scaling (nuclei still in stratum corneum). Increased stratum spinosum; decreased stratum granulosum.
Pinpoint bleeding spots from exposure of dermal papillae when scales scraped off seen in psoriasis.
Inflammatory skin disorder with erythematous papules and pustules.
Flat, greasy, pigmented squamous epithelial proliferation. Look stuck on. Occur on head, trunk, extremities.
sudden apperance of multiple seborrheic keratoses; suggests underlying malignancy
Superficial skin infection caused by S aureus or S pyogenes. Honey colored crusting. S aureus can cause bullae as well.
Infection of dermis and SC tissue. Usually S pyogenes or S aureus.
Inferction of upper dermis and superficial lymphatics. Usually strep pyogenes. Well-defined demarcation between infected and normal skin
Pus walled off within skin. Almost alwyas S aureus
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
Papules caused by poxvirus (dsDNA, replicates in cytoplasm)
Irregular, white, painless plaques on tongue that can't be scraped off. Caused by EBV in immunocompromised patients.
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.
IgG against hemidesmosomes. Tense blisters containing eosinophils on skin. Oral mucosa spared. Linear pattern on IF.
Pruritic papules, vesicles, bullae due to IgA deposits at tips of dermal papillae. Associatd with celica
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
Epidermal hyperplasia causing hyperpigmented thickening of skin in axilla or neck. Associated with high insulin and visceral malignancies
Premalignant lesions caused by sun exposure. Small, rough, red or brown papules or plaques.
Painful inflammatory lesions of subcutaneous fat on anterior shins
Associated with hep C. Pruritic purple polygonal palmar papules and plaques. Wickham strae if mucosal involvement- reticular white lines.
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.
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
Stimulates connective tissue synthesis and remodeling of ECM. Persistently elevated in formation of keloid scars
Can be caused by procollagen peptidase deficiency, reuslting in impaired cleavage of terminal propeptides in ECM.