Key Takeaways for Physical Examination of Skin, Hair, and Nails
Takeaway 1: Use Systematic Visual Inspection with the ABCDE Criteria for Skin Lesions
The ABCDE criteria (Asymmetry, Border irregularity, Color variation, Diameter >6mm, Evolution) is the standardized approach for identifying suspicious skin lesions that require further evaluation. 1
- Asymmetry: Look for moles with irregular shapes where one half doesn't match the other 1
- Border irregularity: Identify lesions with jagged, notched, or blurred edges 1
- Color variation: Note moles with multiple colors or uneven color distribution 1
- Diameter: Pay attention to lesions larger than 6mm 1
- Evolution: Document any changes in size, shape, color, or symptoms over time 1
Apply the "ugly duckling" sign to identify moles that look different from surrounding moles, as these warrant closer scrutiny 1. Remember that melanomas can occur in non-sun-exposed areas, particularly in people with darker skin, who are often diagnosed at later stages 1. The physical examination should include assessment of subcutaneous fat mass, muscle mass, edema, and evaluation of skin, hair, nails, and the oral cavity to note clinical signs of micronutrient deficiencies or excesses 2.
Takeaway 2: Nail Examination Reveals Both Local Pathology and Systemic Disease
Nail abnormalities provide critical diagnostic clues to both localized conditions and underlying systemic diseases that require additional workup. 3
Local Nail Conditions to Identify:
- Onychomycosis: Excessive keratinaceous material under the nail bed in a distal and lateral distribution should prompt evaluation through potassium hydroxide examination of scrapings 3
- Squamous cell carcinoma: A proliferating, erythematous, disruptive mass in the nail bed requires careful evaluation 3
- Longitudinal melanonychia: Vertical nail bands must be differentiated from subungual melanomas, which account for 50% of melanomas in persons with dark skin 3
- Paronychia: Edema and erythema of the proximal and lateral nail folds are hallmark features of acute and chronic paronychia 3
Systemic Disease Indicators:
- Clubbing: May suggest cirrhosis, chronic obstructive pulmonary disease, or celiac sprue 3
- Koilonychia (spoon nail): Commonly associated with iron deficiency anemia 3
- Splinter hemorrhages: May herald endocarditis, although other causes should be considered 3
- Beau lines: Can mark the onset of severe underlying illness 3
- Muehrcke lines: Associated with hypoalbuminemia 3
Nail pain (onychalgia) can accompany both localized and systemic pathology and should be characterized as acute or chronic, intermittent or constant, with attention to exacerbating factors like cold temperatures, touch, or increased activity 4.
Takeaway 3: Perform Hands-On Assessment of Subcutaneous Fat and Muscle Mass
The Nutrition-Focused Physical Exam (NFPE) requires direct palpation and visual assessment to detect subcutaneous fat loss and muscle wasting that may not be apparent from observation alone. 2
Assessment Technique:
- Subcutaneous fat evaluation: Examine fat pads directly below the eyes (should appear as a slight bulge in normally nourished persons but are "hollow" in malnourished persons) and gently pinch the skin above the triceps and biceps to assess fold thickness 2
- Muscle mass assessment: Examine the temporalis muscle, prominence of clavicles, contour of shoulders (rounded indicates well-nourished; squared indicates malnutrition), visibility of scapula, visibility of ribs, interosseous muscle mass between thumb and forefinger, and quadriceps muscle mass 2
The examination should compare the patient's current body habitus with usual BMI and weight changes, and evaluate skin, hair, and nails for clinical signs of micronutrient deficiencies or excesses 2. Risk factors for micronutrient deficiencies include history of bariatric surgery, underlying fatty liver disease, and use of certain medications for common comorbidities 2. Note that excess adiposity may present barriers to accurately assessing muscle wasting or fat loss 2.