External Agents and Their Effects on the Skin
Heat and Cold Injury to the Skin
Type of injury |
Clinical presentation |
Pathology |
Management |
Thermal burn ("rule of nines") |
10, 20, 30 (see table below) |
Coagulation necrosis due to Apoptosis. Non-inflammatory blisters |
Severe : Prevent fluid loss and InfectionMinor: Ice, clean, debride, dress, tetanus treatment |
Sun burn |
Erythma, pain, swelling |
Sunburn cells= apoptotic keratinocytes due to DNA damage. |
Fluids and Tylenol |
Frostbite |
Early :redness and pain from vasoditionLate:whiteness and no- pain due to vasoconstriction Thawing: edema and bleeding blisters |
Cellular necrosis due to tissue anoxia Severe cases result in gangrene |
Rapid thawing in warm H2O or air at or below blood temp. Clean, debride, dress, tetanus treatment. |
Perniosis (Chilblains) |
Red, itchy, painful swellings on fingers/toes after cold exposure. Resolves in warm weather/spring |
Intense upper dermal edema, Lymphocytic vasculitis (monocytes near and in vessel wall) |
Avoid wet/cold conditions, wear gloves etc. Associated with lupus erythematosus |
Cryoglobulinemia |
skin lesions due to cold precipitated proteins (cold exposure provokes symptoms) |
Biopsy: acid-Schiff reagent is bright red in superficial dermal vessels |
Treat underlying disease (malignancy, connective tissue disease, infections) |
Clinical Pathology and Course of Burns
Classification |
Depth of Injury |
Surface |
Sensation |
Outcome |
First-Degree |
Partial epidermis |
Dry, scaling |
Painful |
No scar, heals in 1 week |
Second-Degree Superficial |
Full thickness epidermis |
Blisters, edema |
Painful |
Redness, heals in 3 weeks |
Second-Degree Deep |
Epidermis and superficial dermis |
Blisters, edema, erythema |
Some insensitive areas |
Firm thick scar, loss of hair, >1 month healing |
Third-Degree |
Full thickness skin |
Dry, pearly white or grey |
No sensation |
Total skin loss; Heals by scarring |
Ultraviolet Light and the Skin
Infestations and Infections of Skin
Foreign Bodies and Trauma to the Skin