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CHAPTER SUMMARY FROM THE PHARMACOTHERAPY HANDBOOK
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KEY CONCEPTS
The skin is the largest organ of the human body. It performs many vital functions such as (a) protecting the body against injury, physical agents, and ultraviolet radiation; (b) regulating body temperature; (c) preventing dehydration, thus helping to maintain fluid balance; (d) acting as a sense organ; and (e) acting as an outpost for immune surveillance. Skin also has a role in vitamin D production and absorption.
Age-related factors affect the epidermis and dermis. Pediatric skin is thinner and better hydrated, which enhances topical drug absorption and potential drug toxicities. Elderly skin is drier, thinner, and more friable, which may predispose to external insults.
Patients presenting with a skin condition should be interviewed thoroughly regarding signs and symptoms, urgency, other subjective complaints, and medication history. The skin eruption should be carefully assessed to help distinguish between a disease condition and a drug-induced skin reaction.
Drug-induced skin reactions can be irritant or allergic in nature.
Allergic drug reactions can be classified into exanthematous, urticarial, blistering, and pustular eruptions. Exanthematous reactions include maculopapular rashes and drug hypersensitivity syndrome. Urticarial reactions include urticaria, angioedema, and serum sickness-like reactions. Blistering reactions include fixed drug eruptions, Stevens-Johnson’s syndrome, and toxic epidermal necrolysis. Pustular eruptions include acneiform drug reactions and acute generalized exanthematous pustulosis. Other drug-induced skin reactions include hyperpigmentation and photosensitivity.
Not all skin reactions are drug induced.
Contact dermatitis is a common skin disorder caused either by an irritant or an allergic sensitizer.
The first goals of therapy in the management of contact dermatitis involve identification, withdrawal, and avoidance of the offending agent. A thorough history, including work history, must be carefully reviewed for potential contactants.
Other goals of therapy for contact dermatitis include providing symptomatic relief, implementing preventative measures, and providing coping strategies and other information for patients and caregivers.
Diaper dermatitis is most often seen in infants, although the condition may also be seen in older adults who wear diapers for incontinence. Management includes frequent diaper changes, air drying, gentle cleansing, and using barriers.
Skin cancers include squamous cell carcinoma, basal cell carcinoma, and malignant melanoma.
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Skin is an essential part of the body. Although it is not commonly thought of as such, skin is an organ. In fact, it is the human body’s largest organ, with an average surface area of about 1.8 m2.1 The organ system that includes the skin is known as the integumentary system.
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The human skin consists of an outer epidermis and an inner dermis. The epidermis primarily provides protection from the environment and performs a critical barrier function—keeping in water and other vital substances and keeping out foreign elements. The dermis is a connective tissue layer that primarily provides resiliency ...