·         circumscribed, flat discoloration that measures <1 cm and are nonpalpable

Ex. Becker’s nevus

·         – raised macule.  Confined to the dermis.

o   Wart – papule with scales.

·         – circumscribed, elevated, superficial, and solid lesion > 1cm.  Epidermis only.

Psoriasis – presents as plaques

·         circumscribed, elevated, and solid lesion that goes into dermis. Must squeeze it to differentiate from plaque.  If it is just papule, you will only get the papule.  If it is a nodule, you will feel it deep into the dermis.

Neurofibromatosis – example of nodule and can be either superficial or deep.

·         – circumscribed collection of leukocytes that varies in size. (pimple)

Folliculitis are examples of pustules with erythematous base

·         circumscribed lesion of fluid collection up to 1 cm.  Epidermis only

Ex.  Herpes Simplex – usually presents as collections of vesicles

·         – a large vesicle.  More then 1 cm.

o   Herpes Zoster

·         – Uticaria - firm edematous plaque resulting from the infiltration of dermis with fluid

·         collection of dried serum and cellular debris

Impetigo – scabs surrounding the mouth

·         Focal loss of epidermis.  Does not penetrate into dermis/epidermis junction. 

o   Ex. Tinea Pedis – athletes foot

Heals without scarring

·         – loss of epidermis into dermis.  Results in scarring

o   Chancroid.  Ulcers on the penis.  Differentiated from chancroid by the illiciting of pain.  Syphillis doesn’t hurt.

·         Linear loss of epidermis that extends into the dermis.  Nearly vertical walls

o   Ex. Eczema – hypersensitivity reaction with prolonged inflammation

·         Depression in the skin resulting from the thinning of the epidermis or dermis

Ex.  Caused by over application of topical and intralesional steroids

·         circumscribed and upraised deposit of blood less than .5 cm that does not blanch

·         – circumscribed, upraised deposit of blood greater than .5 cm that does not blanch