Skip to Main Content




The skilful doctor knows by observation, the mediocre doctor by interrogation, the ordinary doctor by palpation.

Chang Chung-ching (c. AD 170–196)


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. 121.1).

  • Patch. Macule of >1 cm diameter (see FIG. 121.1).

  • Papule. Palpable mass on skin surface <0.5 cm diameter (see FIG. 121.2).

  • Maculopapule. A raised and discoloured circumscribed lesion.

  • Nodule. Circumscribed palpable mass >0.5 cm diameter (see FIG. 121.2).

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

  • 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. 121.3).

  • Bulla. A vesicle >0.5 cm diameter (see FIG. 121.3).

  • 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. Bleeding into the skin (dermis) appearing as multiple haemorrhages. May be macular or papular.

  • Petechiae. Purpuric lesions 2 mm or less 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 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. 121.4); they usually heal with scarring.

  • Erosion. A skin defect with complete or partial loss of the epidermis; they heal without scarring (see FIG. 121.4).


Want remote access to your institution's subscription?

Sign in to your MyAccess profile while you are actively authenticated on this site via your institution (you will be able to verify this by looking at the top right corner of the screen - if you see your institution's name, you are authenticated). Once logged in to your MyAccess profile, you will be able to access your institution's subscription for 90 days from any location. You must be logged in while authenticated at least once every 90 days to maintain this remote access.


About MyAccess

If your institution subscribes to this resource, and you don't have a MyAccess profile, please contact your library's reference desk for information on how to gain access to this resource from off-campus.

Subscription Options

Murtagh Collection Full Site: One-Year Subscription

Connect to a suite of general practice resources from one of the most influential authors in the field. Learn the breadth of general practice, including up-to-date information on diagnosis and treatment, as well as key clinical skills like communication.

$145 USD
Buy Now

Pay Per View: Timed Access to all of Murtagh Collection

48 Hour Subscription $34.95

Buy Now

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.