Description Of Primary Skin Lesions

Description Of Primary Skin Lesions:

1. Macule: A flat, colored lesion, <2 cm in diameter, not raised above the surface of the surrounding skin. A "freckle" or ephelid, is a prototype pigmented macule.

2. Patch: A large ( > 2 cm) flat lesion with a color different from the surrounding skin. 

The difference between a macule and a patch is only in size.

3. Papule: A small, solid lesion, < 0.5 cm in diameter, raised above the surface of the surrounding skin and hence palpable. ( e.g a closed comedone or  white-head, in acne)

4. Nodule: A larger (0.5 -5.0 cm), firm lesion raised above the surface of the surrounding skin. Nodule differs from papule only in size. 

5. Tumor: A solid, raised growth > 5 cm in diameter.

6. Plaque: A large (>1 cm), flat topped, raised lesion, edges may either be distinct ( e.g in psoriasis) or gradually blend with surrounding skin. (e.g in eczematous dermatitits) .

7. Vesicle: A small,fluid filled lesion, < 0.5 cm in diameter, raised above the plane of surrounding skin. Fluid is often visible and the lesions are translucent. 

8. Pustule: A vesicle filled with leukocytes. ( it is important to note that the presence of pustules does not necessarily signify the existence of infection. 

9. Bulla: A fluid filled , raised often translucent lesion > 0.5 cm in diameter.

10. Wheal: A raised, erythematous edematous papule or plaque, usually representing short lived vasodilatation and vasopermeability.