Dermatology - Introduction

From Iusmicm

(Difference between revisions)

Revision as of 11:42, 13 October 2011

Motivation

The skin is the biggest, thus most important organ
Skin diseases account for 17% of all primary care visits

Objectives

Basic principles
Introduction to dermatologists
Common skin problems
Complexity of dermatologic disorders

Expectations

Structure and function of the skin
History and physical examination (learn the vocab)
Recognize the clinical (and histologic) hallmarks of diseases discussed
Know how and when to refer a patient

Structure and Function

Three parts: epidermis, dermis, and subcutaneous.
Epidermis:
- Has keratinocytes, melanocytes, and langerhans cells
Dermis:
- Has fibroblasts and blood vessels
Subcutaneous

Keratinocytes

Makes up most of the epidermis.
Keeps in what should be in and out what should be out
Barrier Function: form the stratum corneum
Produce cytokines and inflammatory molecules
Produce antimicrobial proteins and lipids; more potent than anything we can prescribe
Metabolize drugs
Arm skin:
Finger skin:
- Has different keratins than has the arm

Melanocytes

Melanocytes determine how much melanin and therefore the pigmentation of the pt
Produce pigment
Pigment protects against ultraviolet radiation
Vitiligo: loss of melanocytes through autoimmune destruction

Langerhans cells

Macrophage-like cells in epidermis
Important for antigen recognition
About 1/3 of all T cells have been educated in the skin

Fibroblasts

Found in the dermis
Produce collagen and ground substance
Keloid scar is an example of excessive fibroblast activity

Vocabulary

Important for proper communication of observations
Primary versus Secondary lesions
- Primary lesion: basic lesion that defines a disease process
- Secondary lesion: lesions that evolve during the skin disease process or are created by scratching or infection

Primary lesions

Basic lesions that defines a disease process

Macule / Patch

Macule: Circumcised, flat (non-palpable), discolored (hence you can see it)
- Discoloration: brown, blue, red, hypopigmented
- A tattoo is an artificial papule
Large macules (~> 2cm) are called "patches"
- Port-wine stain is an example of a macule

Papule / Plaque

Elevated, solid, 0.5-1 cm diameter
Larger is a plaque
Confluent papules are called "plaques"
Can vary in color
Note that if it is circumscribed it is a nodule

Papules:

Patches:

Nodule / Tumor

Circumscribed, elevated, solid, 0.5-1 cm diameter
Larger is a tumor

Nodule:

Tumor:

Wheal

Firm, edematous plaque resulting because of infiltration of the dermis with fluid
- Example is urticaria (hives) or a TB test
Wheals are transient, may only last hours
http://itsmysocalledlife.files.wordpress.com/2009/02/190px-urtikaria_fuss.jpg%3Fw%3D190%26h%3D143

Pustule

Circumscribed collection of leukocytes and free fluid, varies in size

Vesicle / Bulla

Circumscribed collection of free fluid up to 0.5 cm diameter
- In contrast to a pustule, contents are clear
- Varicella zoster makes vesicles
Bulla is over 0.5 cm diamter
- Look differently depending on where the fluid resides: under the stratum corneum or under the whole epidermis

Vesicles:

Bullae:

Secondary Lesions

Lesions that evolve from pt interaction with a disease process: scratching, picking, et cetera

Scales

Excess dead epidermal cells that are produced by abnormal keratinization and shedding

Crusts (scab) / Erosions

Crust: collection of dried serum and cellular debris (a scab)

Erosion: focal loss of epidermis
- Any scratch that doesn't scar
- Do not penetrate below the dermal-epidermal junction and thus do not scar

Escoriations

Erosion caused by scratching
Often linear

Ulcers

A focal loss of epidermis and dermis
Ulcers heal with scarring

Fissure

Linear loss of epidermis and dermis with sharply defined, vertical walls
- Chapped lips, for example
- Think of corners of mouth

Atrophy

Depression in the skin from thinning of the epidermis or dermis
- feels like cigarette paper
- morvea: localized scleroderma
http://mizzouderm.com/uploads/4/4/2/3/4423869/4212698_orig.jpg?214

Scar

Abnormal form of connective tissue implying dermal damage.
After an injury scars are initially thick and pink and become white and atrophic with time.
To scar, one must get to the dermal papillary level, to the erector pili muscle.
One year until the scar looks like it's final product

Special Lesions

Comedone

Plug of subaceous and keratinaceous debris lodged in the opening of an hair follicle.
- The follicle opening may be widened (blackhead) or narrowed (whitehead).
- A type of acne.

Lichenifcation

Area of thickened epidermis induced by scratching.
- These pts did it to themselves.
Skin lines are accentuated so that the surface looks like a washboard
How many times do you have to scratch yourself to induce lichenification: 200k scratches / rubs to get this response!

Burrow

Narrow, elevated tortuous channel in the skin, created by a parasite
Scabies most common

Milia

Small cysts under the skin; have walls containing epidermis
Associated with scarring; when skin is scarring from injury, skin may form milia
Porphyria can occur secondary to hepatitis C; makes skin of hands fragile, thus producing milia

Cyst

Circumscribed with wall and lumen; may contain solid matter or fluid
- A larger milia

Telangiectasia

Dilated superficial blood vessels
- Can indicate liver disease
Also called spider angiomas is a form of telangiectasias with a lesion
http://www.nytimes.com/imagepages/2007/08/01/health/adam/2998Telangiectasialegs.html

Petechiae / Purpura

Petechiae: circumscribed deposit of blood, < 0.5 cm diameter
Purpura: circumscribed deposit of blood, > 0.5 cm diameter

Petechiae

Purpura:

Examples

Vitiligo: white macule at the nasal bridge, right edge of the nose, and inferior medial border of the right eye
Port-wine stain: red macule across the distributuion of trigeminal V2
Lichen planus: collection of papules forming a plaque on the right hand and wrist, linear in distribution
Deep hemangioma: 2 cm tumor at the lateral, inferior border of the left eye, lacks ulceration, telangeictasia, or eruption

@@ Line 1: / Line 1: @@
 ===Motivation===
-.  The skin is the biggest, thus most important organ
+#The skin is the biggest, thus most important organ
-.  Skin diseases account for 17% of all primary care visits
+#Skin diseases account for 17% of all primary care visits
 ===Objectives===
@@ Line 10: / Line 10: @@
 ===Expectations===
 *Structure and function of the skin
-*History and physical examination
+*History and physical examination (learn the vocab)
 *Recognize the clinical (and histologic) hallmarks of diseases discussed
 *Know how and when to refer a patient
 ===Structure and Function===
+*Three parts: epidermis, dermis, and subcutaneous.
 *Epidermis:
 **Has keratinocytes, melanocytes, and langerhans cells
@@ Line 23: / Line 24: @@
 ====Keratinocytes====
+*Makes up most of the epidermis.
+*Keeps in what should be in and out what should be out
 *Barrier Function: form the stratum corneum
 *Produce cytokines and inflammatory molecules
-*Produce antimicrobial proteins and lipids
+*Produce antimicrobial proteins and lipids; more potent than anything we can prescribe
 *Metabolize drugs
 *Arm skin: http://www.lab.anhb.uwa.edu.au/mb140/corepages/integumentary/Images/skthick0021he.jpg
 *Finger skin: http://www.udel.edu/biology/Wags/histopage/colorpage/cin/cinsgdi.GIF
+**Has different keratins than has the arm
 ====Melanocytes====
+*Melanocytes determine how much melanin and therefore the pigmentation of the pt
 *Produce pigment
 *Pigment protects against ultraviolet radiation
@@ Line 39: / Line 44: @@
 *Macrophage-like cells in epidermis
 *Important for antigen recognition
+*About 1/3 of all T cells have been educated in the skin
 *http://www.technion.ac.il/~mdcourse/274203/slides/Skin/6-Langerhans%20Cells.jpg
 *http://faculty.une.edu/com/abell/histo/thickskin1w.jpg
@@ Line 46: / Line 52: @@
 *Found in the dermis
 *Produce collagen and ground substance
+*Keloid scar is an example of excessive fibroblast activity
 *http://ouhsc.edu/histology/Glass%20slides/43_06.jpg
 *http://www.nature.com/nrc/journal/v6/n5/images/nrc1877-f1.jpg
@@ Line 60: / Line 67: @@
 ====Primary lesions====
+*Basic lesions that defines a disease process
 =====Macule / Patch=====
-*Circumcised, flat ('''non-palpable'''), varies in color
+*Macule: Circumcised, flat ('''non-palpable'''), discolored (hence you can see it)
 **Discoloration: brown, blue, red, hypopigmented
+**A tattoo is an artificial papule
 *Large macules (~> 2cm) are called "patches"
+**Port-wine stain is an example of a macule
 *http://www.websters-dictionary-online.net/images/wiki/wikipedia/commons/thumb/c/c3/Macule.svg/300px-Macule.svg.png
 *http://courses.washington.edu/hubio567/lang/odlnd038.gif
@@ Line 73: / Line 83: @@
 =====Papule / Plaque=====
-*Elevated, solid, 0.5-1 cm diameter
+*'''Elevated''', solid, 0.5-1 cm diameter
 *Larger is a plaque
 *Confluent papules are called "plaques"
@@ Line 118: / Line 128: @@
 =====Wheal=====
-*Firm, edematous plaque
+*Firm, edematous plaque resulting because of infiltration of the dermis with fluid
-*From infiltration of the dermis with fluid
+**Example is urticaria (hives) or a TB test
 *Wheals are transient, may only last hours
 *http://www.skincareguide.ca/images/glossary/wheal.jpg
@@ Line 139: / Line 149: @@
 =====Vesicle / Bulla=====
 *Circumscribed collection of free fluid up to 0.5 cm diameter
+**In contrast to a pustule, contents are clear
+**Varicella zoster makes vesicles
 *Bulla is over 0.5 cm diamter
+**Look differently depending on where the fluid resides: under the stratum corneum or under the whole epidermis
@@ Line 153: / Line 166: @@
 ====Secondary Lesions====
+*Lesions that evolve from pt interaction with a disease process: scratching, picking, et cetera
 =====Scales=====
@@ Line 162: / Line 176: @@
 *http://www.steadyhealth.com/2996/Image/copy-of-psoriasis.jpg
-=====Crusts / Erosions=====
+=====Crusts (scab) / Erosions=====
 *Crust: collection of dried serum and cellular debris (a scab)
 **http://www.dermweb.com/morphology/graphics/morph061.jpg
 **http://www.accessemergencymedicine.com/loadBinary.aspx?fileName=wolf6_c011f019t.jpg
 *Erosion: focal loss of epidermis
+**Any scratch that doesn't scar
 **Do not penetrate below the dermal-epidermal junction and thus do not scar
 **http://www.accessmedicine.ca/loadBinary.aspx?name=wolf7&filename=wolf7_c004f010t.jpg
@@ Line 177: / Line 194: @@
 =====Ulcers=====
-*A focal loss of epidermis AND DERMIS
+*A focal loss of epidermis '''and dermis'''
-*Ulcers heal with scarring.
+*Ulcers heal with scarring
 *http://trialx.com/curetalk/wp-content/blogs.dir/7/files/2011/05/diseases/Skin_Ulcer-2.jpg
 *http://trialx.com/curetalk/wp-content/blogs.dir/7/files/2011/05/diseases/Skin_Ulcer-3.jpg
@@ Line 188: / Line 205: @@
 =====Fissure=====
 *Linear loss of epidermis and dermis with sharply defined, vertical walls
+**Chapped lips, for example
+**Think of corners of mouth
 *http://www.infoderm.com/infoderm/images/las/lesions/Fissure.jpg
 *http://faculty.washington.edu/alexbert/MEDEX/Derm/fisure.gif
@@ Line 196: / Line 215: @@
 =====Atrophy=====
 *Depression in the skin from thinning of the epidermis or dermis
+**feels like cigarette paper
+**morvea: localized scleroderma
 *http://mizzouderm.com/uploads/4/4/2/3/4423869/4212698_orig.jpg?214
 *http://dermimages.med.jhmi.edu/images/Steroid_Atrophy_1_030303.jpg
@@ Line 202: / Line 223: @@
 =====Scar=====
-*Abnormal form of connective tissue implying dermal damage.
+*Abnormal form of connective tissue '''implying dermal damage'''.
 *After an injury scars are initially thick and pink and become white and atrophic with time.
+*To scar, one must get to the dermal papillary level, to the erector pili muscle.
+*One year until the scar looks like it's final product
 *http://www.smartex-balkan.com/wp-content/uploads/2010/09/Keloid-Scar.png
@@ Line 210: / Line 233: @@
 =====Comedone=====
 *Plug of subaceous and keratinaceous debris lodged in the opening of an hair follicle.
-*The follicle opening may be widened (blackhead) or narrowed (whitehead).
+**The follicle opening may be '''widened (blackhead)''' or '''narrowed (whitehead)'''.
+**A type of acne.
 *http://acner.org/img/care_and_prevention/blackheads-on-the-neck_3_3552.jpg
 *http://www.dartmouth.edu/~thabif/weeklyClinic110600/20GiantComedone.jpg
@@ Line 218: / Line 242: @@
 =====Lichenifcation=====
-*Area of thickened epidermis induced by scratching
+*Area of thickened epidermis induced by scratching.
-*Skin lines are accentuated so that the surface looks like a washboard
+**These pts did it to themselves.
+*Skin lines are accentuated so that the surface looks like a '''washboard'''
+*How many times do you have to scratch yourself to induce lichenification: 200k scratches / rubs to get this response!
 *http://missinglink.ucsf.edu/lm/DermatologyGlossary/img/Dermatology%20Glossary/Glossary%20Clinical%20Images/Lichenification-101.jpg
 *http://www.skincareguide.ca/images/glossary/lichen_simplex_chronicus.jpg
@@ Line 225: / Line 251: @@
 =====Burrow=====
 *Narrow, elevated tortuous channel in the skin, created by a parasite
-*Scabies
+*Scabies most common
 *http://i.quizlet.net/i/U7z1SI38X8HldKGXBPWjIQ_m.jpg
 =====Milia=====
 *Small cysts under the skin; have walls containing epidermis
-*Associated with scarring
+*Associated with scarring; when skin is scarring from injury, skin may form milia
+*Porphyria can occur secondary to hepatitis C; makes skin of hands fragile, thus producing milia
 *http://dermnetnz.org/doctors/lesions/images/milia1.jpg
 *http://www.riversideonline.com/source/images/image_popup/fl7_milia.jpg
@@ Line 238: / Line 265: @@
 =====Cyst=====
 *Circumscribed with wall and lumen; may contain solid matter or fluid
+**A larger milia
 *http://meded.ucsd.edu/clinicalimg/upper_inclusion_cyst.jpg
 *http://www.primehealthchannel.com/wp-content/uploads/2010/09/Cyst_Profile2.jpg
@@ Line 247: / Line 275: @@
 =====Telangiectasia=====
 *Dilated superficial blood vessels
-*Also called spinder angiomas
+**Can indicate liver disease
+*Also called spider angiomas is a form of telangiectasias with a lesion
 *http://www.meddean.luc.edu/lumen/MedEd/medicine/dermatology/melton/cyst2.jpg
 *http://www.michmoleremoval.com/sitebuildercontent/sitebuilderpictures/telangiectasia-s.jpg
@@ Line 271: / Line 300: @@
 **http://dermnetnz.org/site-age-specific/img/purpura-s.jpg
 **http://www.skinsite.com/images/batemans%20purpura.gif
+===Examples===
+*Vitiligo: white macule at the nasal bridge, right edge of the nose, and inferior medial border of the right eye
+*Port-wine stain: red macule across the distributuion of trigeminal V2
+*Lichen planus: collection of papules forming a plaque on the right hand and wrist, linear in distribution
+*Deep hemangioma: 2 cm tumor at the lateral, inferior border of the left eye, lacks ulceration, telangeictasia, or eruption

Dermatology - Introduction

From Iusmicm

Revision as of 11:42, 13 October 2011

Contents

Motivation

Objectives

Expectations

Structure and Function

Keratinocytes

Melanocytes

Langerhans cells

Fibroblasts

Vocabulary

Primary lesions

Macule / Patch

Papule / Plaque

Nodule / Tumor

Wheal

Pustule

Vesicle / Bulla

Secondary Lesions

Scales

Crusts (scab) / Erosions

Escoriations

Ulcers

Fissure

Atrophy

Scar

Special Lesions

Comedone

Lichenifcation

Burrow

Milia

Cyst

Telangiectasia

Petechiae / Purpura

Examples

Views

Personal tools

Navigation

Search

EditThis.info tools

Toolbox

Other sites