Chapter 052. Approach to the Patient with a Skin Disorder (Part 4)

Figure 52-5Meningococcemia. An example of fulminant meningococcemia with extensive angular purpuric patches. (Courtesy of Stephen E. Gellis, MD; with permission.)Figure 52-4Necrotizing vasculitis. Palpable purpuric papules on the lower legs are seen in this patient with cutaneous small vessel vasculitis. (Courtesy of Robert Swerlick, MD; with permission.)[newpage]APPROACH TO THE PATIENT: SKIN DISORDERIn examining the skin it is usually advisable to assess the patient before taking an extensive history. This way, the entire cutaneous surface is sure to be evaluated, and objective findings can be integrated with relevant historic data. Four basic features of a skin lesion must be noted and...
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Chapter 052. Approach to the Patient with a Skin Disorder (Part 4) Chapter 052. Approach to the Patient with a Skin Disorder (Part 4)Figure 52-5 Meningococcemia. An example of fulminant meningococcemia withextensive angular purpuric patches. (Courtesy of Stephen E. Gellis, MD; withpermission.) Figure 52-4 Necrotizing vasculitis. Palpable purpuric papules on the lower legs areseen in this patient with cutaneous small vessel vasculitis. (Courtesy of RobertSwerlick, MD; with permission.)[newpage] APPROACH TO THE PATIENT: SKIN DISORDER In examining the skin it is usually advisable to assess the patient beforetaking an extensive history. This way, the entire cutaneous surface is sure to beevaluated, and objective findings can be integrated with relevant historic data.Four basic features of a skin lesion must be noted and considered during aphysical examination: the distribution of the eruption, the types of primary andsecondary lesions, the shape of individual lesions, and the arrangement of thelesions. An ideal skin examination includes evaluation of the skin, hair, and nails aswell as the mucous membranes of the mouth, eyes, nose, nasopharynx, andanogenital region. In the initial examination it is important that the patient bedisrobed as completely as possible. This will minimize chances of missing important individual skin lesionsand make it possible to assess the distribution of the eruption accurately. Thepatient should first be viewed from a distance of about 1.5–2 m (4–6 ft) so that thegeneral character of the skin and the distribution of lesions can be evaluated.Indeed, distribution of lesions often correlates highly with diagnosis (Fig. 52-6).For example, a hospitalized patient with a generalized erythematous exanthem ismore likely to have a drug eruption than is a patient with a similar rash limited tothe sun-exposed portions of the face. Once the distribution of the lesions has beenestablished, the nature of the primary lesion must be determined. Thus, whenlesions are distributed on elbows, knees, and scalp, the most likely possibilitybased solely on distribution is psoriasis or dermatitis herpetiformis (Figs. 52-7 and52-8, respectively). The primary lesion in psoriasis is a scaly papule that soonforms erythematous plaques covered with a white scale, whereas that of dermatitisherpetiformis is an urticarial papule that quickly becomes a small vesicle. In thismanner, identification of the primary lesion directs the examiner toward the properdiagnosis. Secondary changes in skin can also be quite helpful. For example, scale represents excessive epidermis, while crust is the resultof a discontinuous epithelial cell layer. Palpation of skin lesions can also yieldinsight into the character of an eruption. Thus, red papules on the lower extremities that blanch with pressure can bea manifestation of many different diseases, but hemorrhagic red papules that donot blanch with pressure indicate palpable purpura characteristic of necrotizingvasculitis (Fig. 52-4).