Porth's Essentials of Pathophysiology, 4e

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Disorders of Skin Integrity and Function

C h a p t e r 4 6

Age-Related Skin Conditions Some skin problems occur in specific age groups. These include not only birthmarks, but also disorders charac- teristic of childhood, as well as skin changes common in the elderly.

telangiectases found on basal cell carcinomas. Later, lesions grow outward, show large ulcerations, and have persistent crusts and raised erythematous borders. The lesions occur on sun-exposed areas of the skin, particu- larly the nose, forehead, helix of the ear, lower lip, and back of the hand. Invasive squamous cell carcinoma has the potential to recur and metastasize. Chief among the risk factors for tumor recurrence and metastasis are the size and location of the tumor. 70 Large lesions (>2 cm in diameter), tumors of the lip and ear, tumors arising in injured or chronically diseased skin, and rapidly grow- ing lesions are at particular risk. Treatment measures are aimed at the removal of all cancerous tissue using methods such as electrosurgery, excision surgery, chemosurgery, or radiation therapy. After treatment, the person is observed for the remain- der of his or her life for signs of recurrence. ■■ Nevi or moles usually are benign neoplasms of the skin. Because they may undergo cancerous transformation, any mole that changes warrants immediate medical attention. ■■ Repeated exposure to the UV rays of the sun has been implicated as the principal cause of skin cancer. ■■ The melanocytes, which protect against sunburn through increased production of melanin, are particularly vulnerable to the adverse effects of unprotected exposure to ultraviolet light. Malignant melanoma, which is a cancerous tumor of melanocytes, is a rapidly progressive and metastatic form of skin cancer.The most important clinical sign is the change in size, shape, and color of pigmented skin lesions, such as moles. As the result of increased public awareness, melanomas are now more likely to be diagnosed at an earlier stage, when they can be cured surgically. ■■ Basal cell carcinoma, which is a neoplasm of the nonkeratinizing cells of the basal layer of the epidermis, is the most common skin cancer in light-skinned people. It is slow-growing and rarely metastasizes. ■■ Squamous cell tumors resemble the epidermal cells of the stratum spinosum to varying degrees and extend into the adjacent dermis. Squamous cell carcinoma may remain confined to the epidermis for a period of time, but at some unpredictable time, it becomes invasive and metastasizes to the regional lymph nodes. Chief among the risk factors for tumor invasion and metastasis are the size and location of the tumor. SUMMARY CONCEPTS

Skin Manifestations of Infancy and Childhood

Infancy connotes the image of perfect, unblemished skin. For the most part, this is true. However, several acquired skin conditions, including diaper dermatitis, prickly heat, and cradle cap, are relatively common in infants. Moreover, congenital skin lesions, such as Mongolian spots, hemangiomas, and nevi, are associ- ated with the neonatal period, and many childhood infections are commonly accompanied by skin changes. Skin Disorders of Infancy Throughout infancy, the skin is especially sensitive to irritation from harsh chemicals, humidity, and heat. Diaper Dermatitis. Irritant diaper dermatitis, or diaper rash, is a form of contact dermatitis caused by the inter- action of several factors, including prolonged contact of the skin with a mixture of urine and feces. The appear- ance of diaper rash ranges from simple (i.e., widely dis- tributed macules on the buttocks and anogenital areas) to severe (i.e., beefy, red, excoriated skin surfaces in the diaper area). Secondary infections with bacteria and yeasts are common; discomfort may be marked because of intense inflammation. Such conditions as contact dermatitis, seborrheic dermatitis, candidiasis, and atopic dermatitis should be considered when the erup- tion is persistent and recalcitrant to simple therapeutic measures. Diaper dermatitis often responds to simple measures, including frequent diaper changes with careful cleansing of the irritated area to remove all waste products. Feces in particular should be removed from the skin as soon as possible after the diaper has been soiled. Because soap and lipid solvents remove protective lipids from the stra- tum corneum, using water or an alcohol-free baby wipe is recommended. Exposing the irritated area to air is helpful. It has been shown that application of a barrier ointment after each diaper change is a valuable compo- nent of therapy. Topical corticosteroid therapy is usually effective, but should be used cautiously because infants absorb proportionately greater quantities through their skin than adults. Antifungal therapy should not be used routinely, but can be helpful when Candida infection is established or suspected. Antibacterial agents should not be used because bacterial infections are rarely involved in diaper dermatitis, and the normal microflora should be preserved. Intractable and severe cases of diaper dermatitis should be seen by a health care provider for treatment