Dermatology Flashcards
Bullous pemphigoid
antibodies to hemidesmosomes (connect basal keratinocytes to basement membrane in basal layer of epidermis)
Pemphigus vulgaris
antibodies to desmosomes (connect keratinocytes to each other in epidermis)
Xeroderma pigmentosum
AR genetic disorder in which the pt has ineffective DNA repair mechanisms; results in several base cell carcinomas, malignant melanomas, and squamous cell carcinomas in XP pts who are exposed to sunlight
Hypohidrotic ectodermal dysplasia
thermoregulation disorder:
mutation in EDAR gene (protein for proper interaction btw developing ectoderm and mesoderm) results in an inability to regulate temperature, so these pts overheat easily, and also have abnormal hair follicles, sweat glands, and teeth
What are the 3 layers of the skin and their resident cells?
Epidermis - keratinocytes, melanocytes, Langerhans cells, Merkel cells
Dermis - fibroblasts, collagen, elastic, blood vessels, nerve endings
Subcutis - fat, blood vessels, fibrous septae
What are the 4 layers of the Epidermis and their resident cells/materials?
BOTTOM - stratum basale/basal layer, stem cells that give rise to new KCs
Next up - stratum spinosum, where the cells differentiate and appear spiny because of the visible desmosomes connecting the KC to each other; also has lamellar (lipid) granules for barrier function
Almost to the top - stratum granulosum, where the cells appear granular because they are synthesizing the IC keratohyaline granules; also here the lamellar granules are secreted into the ECM for water barrier
TOP - stratum corneum, where the cells are flat and function as the barrier-most layer where keratins and filaggrins create protective layer and keep water in the cells
Melanocytes
melanin (pigment) -producing dendritic cells derived from neural crest; located among the basal cells in the epidermis, about 1MC:10KCs
Langerhans cells
Dendritic cells (APCs) in mid-epidermis; they recognize antigens, phagocytose, process, and present to LCs in regional lymph nodes
Merkel cells
epidermal cells associated with light touch sensation
Apocrine vs. Eccrine sweat glands
Apocrine glands are associated with hair follicles, component of the pilosebaceous unit
Eccrine glands are the “true” sweat glands that open directly onto the skin (not associated with hair follicle)
Epidermolysis Bullosa Simplex
genetic mutation in keratin 5 or 14; causes blistering and basal KC fragility, so the KCs break off when they should be attached by keratins to the hemidesmosome plate
Psoriasis
- long-lasting autoimmune disease characterized by patches of abnormal skin that are typically red, itchy, and scaly.
- etiology unknown but believed to be based in genetics, chronic infections, HIV, or drug-induced
- highly associated with metabolic syndrome, CVD, and obesity
Toxic epidermal necrolysis
often drug-induced, acute (dermatologic emergency) necrosis and sloughing of the epidermis
Atopic dermatitis
inflammatory condition of the skin that results in itchy, red, swollen, and cracked skin; cause is not known but believed to involve genetics, immune system dysfunction, environmental exposures, and difficulties with the permeability of the skin
Tx algorithm for acne
Mild comedonal: Top. retinoid
Mild inflammatory/mixed: Top. retinoid + top. abx
Moderate inflammatory/mixed: top. retinoid + top. abx + oral abx
Severe inflammatory/refractory to treatment:
minimal scarring: top. retinoid + top. abx + oral abx
scarring/multiple tx failures: Isotretinoin
Topical combos: Tretinoin + clindamycin
Adapalene + benzoyl peroxide