1. An inflammation of the skin that usually represents an allergic response to a variety of agents such as Poison Ivy; most common inflammatory skin disease; 3 stages and can start from any of the 3 stages; typically a Type IV delayed hypersensitivity reaction; scratching can cause a linear lesion; begins within hours and can last up to weeks; pruitis
    - bright red swollen plaque with pebbly surface that evolved in hours
    - pebbles are vesicles
    - may progress to a blister
    • Acute Eczematous Dermatitis
    • Physical: Erythema and scale are always major; do not have distinct borders
    • Histology: intraepithelial vesicle/bulla; intracellular edema (spongiosis); mononuclear infiltrate
    • Treatment: cool wet dressing; antihistamine; predisone 20 mg; antibiotics for secondary infection
  2. An allergic reaction dermatitis:
    - pruritus ranges from none to severe
    - variable course, may spontaneously regress
    - causes of acute changing are infection, continued allergens, scratching, wet dressings
    • Subacute Eczematous Dermatitis
    • Treatment = topical steroids are treatment of choice
  3. May follow a bout of acute; may begin primarily as in lichen simplex chronicus
    Inflamed area thickens and surface skin markings become more prominent
    border usually well defined but not crisp
    • Chronic Eczematous Dermatitis
    • differential - fungus, psoriasis
    • Treatment - topical steroids (can't leave on > 12 hours)
  4. An eczematous dermatitis caused by exposure to a substance in the environment
    • Contact Dermatitis
    • - most common cause = irritation to the skin
  5. Four basic layers of the epithelium
    • 1. Stratum basale: all mitosis here
    • 2. Stratum Spinosum
    • 3. Stratum granulosum: Keratin
    • 4. Stratum corneum
  6. This layer is mitotically active and produces cells that form other layers - keratinocytes
    small cuboidal or low columnar
    are basophilic on routine H&E staining
    Stratum Basale
  7. cells in this layer are tied together by cytoplasmic desmosomes
    intracellular bridges
    Stratum Spinosum
  8. contains basophilic keratohyalin granules (rich proteins)
    produces keratin, the layer above this
    the most superficial of nonkeratinized epithelium
    Stratum Granulosum
  9. composed of anucleate cells filled with keratin;
    plasma membrane is coated with a glycolipid
    this layer with the coating is the major water barrier of the skin
    Stratum Corneum
  10. dermal papillae project upward into epithelium
    rete ridges project downward
    responsible for fingerprints
  11. 4 basement membrane layers
    cancer has to break through these to metastasize
    • 1. Basal cell plasma membrane
    • 2. Lamina lucida: area that is the weakest, most AT:AB rxn occur
    • 3. Lamina densa
    • 4. Sublamina densa including anchoring fibrils; strongest layer
Card Set
Dermatology A