Principles of dermatological practice

Examination of the skin

Created 2008.

Learning objectives

  • Develop skills in examination of the skin.

Introduction

The entire skin surface should be examined as well as hair, nails and mucosal surfaces. This may require a chaperone. Explain the necessity of complete examination to the patient. Use an appropriate light source and magnification. Identify the presenting complaint and incidental skin conditions (especially skin cancers). Have you found solitary lesions or a widespread rash?

Assess distribution, morphology and arrangement i.e. the number, size and colour of skin lesions, which sites are involved, their symmetry, shape and arrangement. What types of lesions are present? (The next section of this course outlines the correct terminology to use.)

Touch the skin to palpate individual lesions and more diffuse rashes, noting surface and deep characteristics. Does the lesion involve epidermis, dermis or subcutis? If scaly, does the surface flake off easily? If crusted, what is underneath?

Look carefully for signs of systemic disease, such as xanthomas (hyperlipidaemia), café-au-lait macules (neurofibromatosis), acanthosis nigricans (insulin resistance) etc.

Examine the hair and nails (described in later sections of this course). Mucosal surfaces include conjunctivae, lips, gums, tongue, and buccal mucosa. Genital examinations are only required if related to the presenting complaint. Specific permission should be obtained for genital examination and a chaperone should be available to the patient.

Finally, where indicated by symptoms or clinical signs, perform a general physical examination that may include height, weight, temperature, cardiovascular/respiratory assessment and so on.

Special examinations

Specialised techniques used in examination of the skin include:

  • Dermoscopy for pigmented lesions to diagnose melanoma.
  • Skin biopsy for histology and direct immunofluorescence.
  • Patch tests to identify type 4 contact hypersensitivity reactions.
  • Skin scrapings or nail clippings for mycology (fungal infections).
  • Wood's light (long wave UVA) examination for pigmentary changes and fluorescence resulting from certain infections.

Less dermatologically specific tests include:

  • Skin swabs and smears for bacteria yeast and viral infections.
  • Blood tests for culture, serology, haematology, biochemistry etc.
  • Urine tests for culture, biochemistry etc.
  • Faecal tests for culture, occult blood testing, biochemistry
  • X-rays for systemic disease, bone abnormalities
  • Selected prick tests to identify Type 1 hypersensitivity reactions.

These procedures will be described in later topics where relevant to specific skin conditions.

Activity

Discuss the difficulties of examining the skin during a telemedicine consultation using still or video images.

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Related information

References:

Other websites:

Books about skin diseases:

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