HLTH 2501: skin disorders Flashcards
skin lesion causes
systemic disorders such as liver disease, systemic infections like chickenpox, allergies to food or drugs, or exposure to toxics
what are lesions classified on?
their physical appearance (colour, elevation, texture), type of exudate, and the presence of pain or itching
types of lesions
macule, papule, nodule, pustule, vesicle, plaque, crust, lichenification, keloid, fissure, ulcer, erosion, or comedone
macule
small, flat, circumscribed lesion of a different colour than the normal skin
papule
small, firm, elevated lesion
nodule
palpable, elevated lesion that varies in size
vesicle
elevated, thin-walled lesion containing clear fluid (blister)
pustule
elevated, erythematous lesion, usually containing purulent exudate
crust
dry, rough surface or dried exudate or blood
lichenification
thick, dry, rough surface (leathlike)
keloid
raised, irregular and increasing mass of collagen resulting from excessive scar tissue formation
fissure
small, deep, liner crack or tear in skin
ulcer
cavity with loss of tissue from the epidermis and dermis, often weeping or bleeding
erosion
shallow, moist cavity in epidermis
comedone
mass of sebum, keratin, and debris blocking the opening of a hair follicle; blackheads and whiteheads
what is pruritus associated with?
allergic reactions, chemical irritation, insect bites, or infections by parasites
example of a parasite that causes itching
scabies mites
why does pruritus occur?
it is not totally understood but histamine release causes this as well as mild stimulation of pain receptors by irritants
why may secondary infections occur with itching?
because microbes from under the nails may enter into the skin via stratching
testing for bacterial infections
includes culture and staining of specimens for identification
testing for fungal or parasitic infections
includes microscopic examination, sample culturing, direct observation, and other procedures such as UV light or Wood’s lamb
testing for malignant changes in tissue
may be done by biopsy
testing for allergy or abnormal immune responses
can be done via blood tests or scratch tests
testing for drug reactions
uses specific antibody-antigen testing
treatment for pruritus
antihistamines or glucocorticoids, avoiding allergies, and soaks or compresses
how may precancerous lesions by removed?
surgery, laser therapy, electrodessication, or cryosurgery
electrodessication
removing precancerous lesions via heat
cryosurgery
removing precancerous lesions via freezing by liquid nitrogen
how do topical agents reduce itching?
some hae a local anesthetic to reduce itching and burning sensations
what do burns cause?
an acute inflammatory reaction
contact dermatitis
may be caused by exposure to an allergen or by direct chemical or mechanical irritation of the skin
allergy dermatitis
may result from exposure to any of multiple substances, including metals, cosmetics, soaps, chemicals, and plants