Skin examination

The visual examination of the skin requires adequate light to ensure that the subtle changes in surface texture and colour are visible. Ideally natural sunlight is preferred, although additional artificial light may be used, such as a focused lamp with a magnification facility. Before examining for lesions, it is necessary to assess the general condition of the skin. One important general feature is skin turgor, which provides an indicator of hydration - by pulling the skin together in a gentle pinch-like movement and then examining the rapidity with which it returns to its original position - elasticity and moisture level. Good sites to test the skin turgor include the back of the hand and between the thumb and forefinger. A delayed period over which it returns to its normal shape may be an indication of dehydration. This is distinct but related to the elasticity of the skin, which is also dependant on its protein structure.

It is also necessary to assess the skin appendages such as nails and hair, which may provide an indication of generalised disease such as psoriasis or localised pathology. For example, nail infections (paronychia) can cause distortion and brittleness to finger and toenails and scalp psoriasis produces scalp scaling. Abnormalities in the appendages may also provide clues as to general health; for example clubbed nails may be an indication of poor nutritional status or disease such as pulmonary or inflammatory bowel disease (Fawcett et al., 2004).

Palpation is important to distinguish some surface features such as warty, degree of scaling and the solidity of a lesion. Colour changes reflect the presence of factors such as the local microcirculation and inflammatory changes to the existence or absence of certain pigments, such as melanin (e.g. as in vitiligo). Other colour changes may be due to the presence of pigments such as haemosiderin, a brown-pigmented material found in skin affected by venous isease. To determine abnormal variations in colour change, it is often useful to examine the extremities such as the nails, lips and ear lobes, which can provide acces sible indications of colour change. Technological aids may also enhance skin assessment; these are discussed later in this section.