Chapter 111: A diagnostic and management approach to skin problems

INTRODUCTION

The diagnosis of skin problems depends on astute clinical skills based on a systematic history and examination and, of course, experience. If the diagnosis is in doubt, it is appropriate to refer the patient to a skilled cooperative consultant, as the referral process is an excellent educational opportunity for the GP. Another opinion from a colleague/s in a group practice is also very educative. At least, cross-referencing the skin lesion with a colour atlas facilitates the learning process.

TERMINOLOGY OF SKIN LESIONS

Primary lesions

• Macule. Circumscribed area of altered skin colour (Latin for stain) without elevation <1 cm diameter (see FIG. 111.1).

• Patch. Macule of >1 cm diameter (see FIG. 111.1).

• Papule. Palpable mass on skin surface <1 cm diameter (see FIG. 111.2).

• Plaque. A flat-topped palpable mass >1 cm diameter.

• Nodule. A circumscribed, solid palpable mass >1 cm diameter (see FIG. 111.2).

• Wheal. An area of dermal oedema (can be any size), which is pale and compressible.

• Angio-oedema. A diffuse area of oedema extending into subcutaneous tissue.

• Vesicle. A fluid-filled blister <0.5 cm in diameter (see FIG. 111.3).

• Bulla. A vesicle >0.5 cm diameter (see FIG. 111.3).

• Pustule. A visible collection of pus in the skin <1 cm diameter.

• Abscess. A localised collection of pus in a cavity >1 cm diameter

• Furuncle. A purulent infected hair follicle; includes:

  • – folliculitis (small furuncles)

  • – boils (larger furuncles)

• Carbuncle. A cluster of boils discharging through several openings.

• Purpura. A circumscribed deposit of blood >0.5 cm in diameter. May be palpable or non-palpable.

• Petechiae. Purpuric lesions <0.5 cm in diameter.

• Ecchymosis. Larger purpuric lesion.

• Haematoma. A swelling from gross bleeding.

• Telangiectasia. Visible dilatation of small cutaneous blood vessels.

• Comedo. A plug of keratin and sebum in a dilated pilosebaceous gland.

• ‘Blackhead’. An open comedo.

• ‘Whitehead’. A closed comedo.

• Erythema. Redness of the skin due to increased vascularity.

• Milium. Tiny white cyst containing keratin, from occlusion of pilosebaceous gland.

• Papilloma. Warty projection above the skin surface.

Secondary lesions

• Scales. An accumulation of excess keratin of the stratum corneum that presents as flaking.

• Crusts (scabs). Superficial dried secretions (serum and exudate).

• Ulcer. A circumscribed deep defect with loss of all the epidermis and part or all of the dermis (see FIG. 111.4); they usually heal with scarring.

• Erosion. A skin defect with complete ...