Define and give an example of the following primary skin lesions macule papule plaque

Before you can make a diagnosis of any skin lesion, it's important to be able to accurately describe the skin lesion. The purpose of this page is to cover the fundamental knowledge you will need to do this. 

1. Primary Morphology
   1. Macule - flat lesion less than 1 cm, without elevation or depression
   2. Patch - flat lesion greater than 1 cm, without elevation or depression
   3. Plaque - flat, elevated lesion, usually greater than 1 cm
   4. Papule - elevated, solid lesion less than 1 cm
   5. Nodule - elevated, solid lesion greater than 1 cm
   6. Vesicle - elevated, fluid-filled lesion, usually less than 1 cm 
   7. Pustule - elevated, pus-filled lesion, usually less than 1 cm
   8. Bulla - elevated, fluid-filled lesion, usually greater than 1 cm 
2. Size
3. Demarcation
   1. Well-demarcated
   2. Not well-demarcated
4. Color
   1. White
   2. Red
   3. Purple
   4. Brown
   5. Yellow
   6. Black
   7. Blue
5. Secondary Morphology
   1. Serum (Dry crust)
   2. Fissure
   3. Lichenification
   4. Erosion
   5. Ulceration
   6. Scaling
6. Distribution
   1. Extensor
   2. Generalized
   3. Photodistributive 

Macule

Example: Petechiae

Plaque

Example: Psoriasis

Papule

Examples: Angioma, Wart

Nodule

Example: Epidermal Inclusion Cyst

Bullae

Example: Bullous pemphigoid

How Small?

Example: Superficial Spreading Melanoma

How Large?

Example: Acral Lentiginous Melanoma

Clearly Defined?

Example: Erysipelas

Not Well Defined?

Example: Cellulitis

Justin Ko

Dr. Justin Ko is a Clinical Assistant Professor, Dermatologist and Clinic Chief and Director of Medical Dermatology at Stanford.

Clinical Pearl

A good dermatology exam requires a well lit room and sometimes a hand held light. Sometimes, you may need a ruler and magnifiying glass. Remember that sometimes the palpation of skin lesions can be just as important as what you see.

Red

Example: Drug Eruption

Purple

Example: Kaposi Sarcoma

Brown

Example: Sarcoidosis

Yellow

Example: Xanthelasma

Black

Example: Black Eschar

Serum (Dried Crust)

Example: Impetigo

Fissure

Example: Psoriasis

Lichenification

Thickening of skin. Note the accentuation of skin lines

Example: Chronic Rubbing, Lichen simplex chronicus

Erosion

Partial loss of epidermis.

Example: Scratching, minor skin injury

Ulceration

Full thickness loss of epidermis. 

Example: Pyoderma gangrenosum, Pressure/Decubitus ulcer

Scaling

Example: Psoriasis (picture), Ichthyosis

Extensor surfaces

Example: Psoriasis

Generalized

Example: Viral, Drug reaction

Photodistributive

Example: Lupus / Dermatomyositis

Applying What We Learned

Based on the above image, here's how we'd describe this skin lesion:

1. Primary morphology -> plaque, 
2. Size -> a few centimeters 
3. Well-Demarcated
4. Color -> Dully red
5. Secondary morphology -> Dry serum/crusting, erosions and scaling
6. Distribution -> Extensor surface of leg

Diagnosis is consistent with psoriasis given the above description.

The identification Identification Defense Mechanisms and classification of skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions lesions in a patient are important steps in the diagnosis of any skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions disorder. Primary lesions represent the initial presentation Presentation The position or orientation of the fetus at near term or during obstetric labor, determined by its relation to the spine of the mother and the birth canal. The normal position is a vertical, cephalic presentation with the fetal vertex flexed on the neck. Normal and Abnormal Labor of the disease process. Secondary lesions develop from irritated or manipulated primary lesions, and/or disease progression. Along with history, a comprehensive examination of the skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions, appendages, and mucous membranes is required to differentiate between conditions. The key features noted during examination include the type, morphology, size, color, shape, arrangement, and distribution of the presenting lesions. At times, diagnostic procedures may be necessary.

Last updated: Nov 29, 2021

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