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.
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.