Primary Dermatological Lesions
Primary lesions are ...

Primary Dermatological Lesions
Primary lesions are physical changes in the skin considered to be caused directly by the disease process.
Types of primary lesions are rarely specific to a single disease entity.

A. BURROW: burrows are linear/curvilinear lesions produced by infestation of the skin and formation of tunnels (namely by the scabitic mite or by cutaneous larva migrans).

B. COMEDONE: a plug of keratin and sebum wedged in a dilated pilosebaceous orifice 

C. MACULE: a circumscribed flat area of altered colour e.g. freckle. A macule greater than 1 cm. may be referred to as a patch.

D. PAPILLOMA: a projecting nipple-like mass e.g. skin tag 

E. PAPULE: a discrete elevation of skin that may be changed in colour. Those arising from the subcutis may be felt rather than seen. Larger lesions (>1 cm) are referred to as nodules. Papules may have a variety of shapes in profile (domed, flat-topped, umbilicated) and may be associated with secondary features such as crusts or scales.

F. PETECHIAE and PURPURA: Petechiae are pinhead-sized flat macules of extravascular blood in the dermis.

                                                          Purpura are larger and may be palpable

                                                          Ecchymosis ('bruise') is where bleeding involves deeper structures 

G. PLAQUE: solid, raised, flat-topped area of skin greater than 1cm in diameter. It is analogous to the geological formation, the plateau. e.g. psoriasis plaque

H. PUSTULE: circumscribed elevated lesions that contain pus. They are most commonly infected (as in folliculitis) but may be sterile (as in pustular psoriasis)

I. SCALE: flake-like compacted desquamated layers of stratum corneum. Desquamation occurs when there are peeling sheets of scale following acute injury to the skin. e.g. psoriasis

J. TELANGIECTASIA: visible (and permanent) dilatation of small cutaneous blood vessels in the skin. Can be isolated lesions or part of a generalized disorder, such as ataxia telangiectasia.

K. VESICLE and BULLA:  small (few mm) and larger (several cm) fluid-filled blisters respectively. Filled with clear fluid. e.g. pemphigoid

L. WEAL: an area of dermal oedema, usually white due to masking of local blood supply by fluid, e.g. nettle sting

#Diagnosis #Dermatology #Skin #Primary #Lesions #Terminology #Nomenclature #Atlas #Key #Basics
Contributed by

Dr. Gerald Diaz
Board Certified Internal Medicine Hospitalist, GrepMed Editor in Chief πŸ‡΅πŸ‡­ πŸ‡ΊπŸ‡Έ - Sign up for an account to like, bookmark and upload images to contribute to our community platform. Follow us on IG: | Twitter:
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