D ERMATOLOGY

P HYSIOOGIC CONCEPTS Many different lesions occur on the skin. They are described on the basis of size, depth, color, and consistency. Erosion An erosion is loss of superficial epidermis. Typically the area is moist, but it does not bleed (e.g., the skin after bursting of a blister or vesicle). Fissure A fissure is a linear crack in the skin, for example, as seen with athlete's foot. The fissure may be pink or red, but there is usually no bleeding.

P HYSIOLOGIC CONCEPTS Macule A macule is a flattened area of the skin, smaller than 1.0 cm in diameter characterized by a change in color. Papule A papule is a solid, elevated mass, smaller than 1.0 cm in diameter. Examples of papules include elevated moles and warts. Petechia A deep red spot of pinpoint hemorrhage under the skin. Petechiae may signify a bleeding disorder or fragility of the capillaries and may accompany a serious infection.

Pruritus It refers to itching of the skin. Pruritus may occur as a primary response to a surface irritant or inflammation, for example, after a mosquito bite. Pruritus may occur secondarily to a systemic disease, such as liver or kidney failure.

P HYSIOLOGIC CONCEPTS Scar A scar is an area of the body where the skin has been replaced by fibrous tissue (e.g., a burn scar). Ulcer An ulcer is an area with loss of epidermal and deeper layers of the skin that may bleed and scar. An example of an ulcer is a decubitus ulcer (pressure sore).

C ONDITIONS OF D ISEASE OR I NJURY 1-Contact Dermatitis; an acute or chronic inflammation of the skin caused by exposure to an irritant (irritant dermatitis) or allergen (allergic dermatitis). Common causes of irritant dermatitis include soaps, detergents and household cleaners. Clinical Manifestations; localized redness and oozing vesicles in an area of contact. Pruritus may be intense. Allergic dermatitis typically presents 1 to 2 days after exposure.

D IAGNOSIS A good history is the key to diagnosis. A circle of lesions around the wrist may indicate an allergy to a bracelet or watch, Lesions below the umbilicus may indicate an allergy to the metal of a zipper. Reddened, irritated hands may indicate a response to dishwashing. Treatment Identifying the cause. Cool compresses reduce inflammation. Antihistamines may be used to reduce itching. Short-term, topical steroidal therapy, IV for severe attack.

BURNS Burns may result from exposure of the skin to high temperature, electrical shock, or chemicals. Burns are classified according to tissue depth of the burn and the extent of the body surface area Depth of a Burn A first-degree burns are limited to the epidermis. There is erythema and pain but no immediate blistering. The burn does not scar. There are usually no complications. A second-degree burns extend through the epidermis and into the dermal layer, extremely painful and blisters within minutes. Complications are uncommon, infection of the wound may occur. A third-degree burns extend through the epidermis and the dermis and into the subcutaneous tissue layer. Blood vessels and Nerves are destroyed, not painful, although surrounding areas typically show extremely painful. surgical debridement and grafting are necessary. Fourth-degree burns extend through muscle, bone, and internal tissues

E XTENT OF A B URN The percentage of TBSA (total body surface area)affected is estimated. rule of nines. With this method, each arm is considered 9% of the body surface area, each leg 18%,the front and back torso each 18%, the head 9%, and the genital area 1%. Based on TBSA burned, major burns are defined as those involving between 25% and 40% of the body surface area of an adult and between 15% and 25% of the surface area of a child. Burns of greater than 40% in adults or 25% in children are associated with significant mortality. Besides considering TBSA burned and depth of burns, the overall health and age of the individual must be taken into consideration when predicting survival from any burn. Children and the elderly have increased mortality compared with middle-aged and young adults. An individual suffering from a severe burn should be transferred to a burn care facility as soon as possible.

T REATMENT First Aid, cool water - The application of ice should be avoided because ice decreases blood flow to the area. - Clothes should not be removed from a serious burn, - Individuals who have a severe burn must receive medical treatment. - Burns to the hands, face, and genitals should be evaluated by medical personnel. - First-degree burns usually require only prolonged exposure to large amounts of cool water or the application of cool compresses and anti- inflammatory medication. - First-degree chemical burns should be flushed with cool water for several minutes. - Burns deeper than first-degree require antimicrobial therapy - Major burns require quick intravenous fluid replacement to combat the loss of capillary seal. To maintain blood pressure and prevent irreversible shock, infusions in an adult may reach 30L in 24 hours. The high rate of fluid replacement also flushes the kidney and reduces the risk of renal failure.