derm.txt

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

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

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

An eczematous dermatitis caused by exposure to a substance in the environment

Four basic layers of the epithelium

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

cells in this layer are tied together by cytoplasmic desmosomes
intracellular bridges

contains basophilic keratohyalin granules (rich proteins)
produces keratin, the layer above this
the most superficial of nonkeratinized epithelium

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

dermal papillae project upward into epithelium
rete ridges project downward
responsible for fingerprints

4 basement membrane layers
cancer has to break through these to metastasize