Dermatology - Introduction
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(Created page with '===Motivation=== 1. The skin is the biggest, thus most important organ 2. Skin diseases account for 17% of all primary care visits ===Objectives=== *Basic principles *Intro…') |
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===Motivation=== | ===Motivation=== | ||
- | + | #The skin is the biggest, thus most important organ | |
- | + | #Skin diseases account for 17% of all primary care visits | |
===Objectives=== | ===Objectives=== | ||
Line 10: | Line 10: | ||
===Expectations=== | ===Expectations=== | ||
- | *Structure and function of the skin | + | *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 | + | *Recognize the clinical (and histologic) hallmarks of diseases discussed |
- | *Know how and when to refer a patient | + | *Know how and when to refer a patient |
===Structure and Function=== | ===Structure and Function=== | ||
+ | *Three parts: epidermis, dermis, and subcutaneous. | ||
*Epidermis: | *Epidermis: | ||
**Has keratinocytes, melanocytes, and langerhans cells | **Has keratinocytes, melanocytes, and langerhans cells | ||
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====Keratinocytes==== | ====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 | *Barrier Function: form the stratum corneum | ||
*Produce cytokines and inflammatory molecules | *Produce cytokines and inflammatory molecules | ||
- | *Produce antimicrobial proteins and lipids | + | *Produce antimicrobial proteins and lipids; more potent than anything we can prescribe |
*Metabolize drugs | *Metabolize drugs | ||
*Arm skin: http://www.lab.anhb.uwa.edu.au/mb140/corepages/integumentary/Images/skthick0021he.jpg | *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 | *Finger skin: http://www.udel.edu/biology/Wags/histopage/colorpage/cin/cinsgdi.GIF | ||
+ | **Has different keratins than has the arm | ||
====Melanocytes==== | ====Melanocytes==== | ||
+ | *Melanocytes determine how much melanin and therefore the pigmentation of the pt | ||
*Produce pigment | *Produce pigment | ||
*Pigment protects against ultraviolet radiation | *Pigment protects against ultraviolet radiation | ||
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*Macrophage-like cells in epidermis | *Macrophage-like cells in epidermis | ||
*Important for antigen recognition | *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://www.technion.ac.il/~mdcourse/274203/slides/Skin/6-Langerhans%20Cells.jpg | ||
*http://faculty.une.edu/com/abell/histo/thickskin1w.jpg | *http://faculty.une.edu/com/abell/histo/thickskin1w.jpg | ||
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*Found in the dermis | *Found in the dermis | ||
*Produce collagen and ground substance | *Produce collagen and ground substance | ||
+ | *Keloid scar is an example of excessive fibroblast activity | ||
*http://ouhsc.edu/histology/Glass%20slides/43_06.jpg | *http://ouhsc.edu/histology/Glass%20slides/43_06.jpg | ||
*http://www.nature.com/nrc/journal/v6/n5/images/nrc1877-f1.jpg | *http://www.nature.com/nrc/journal/v6/n5/images/nrc1877-f1.jpg | ||
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====Primary lesions==== | ====Primary lesions==== | ||
+ | *Basic lesions that defines a disease process | ||
=====Macule / Patch===== | =====Macule / Patch===== | ||
- | *Circumcised, flat ('''non-palpable'''), | + | *Macule: Circumcised, flat ('''non-palpable'''), discolored (hence you can see it) |
**Discoloration: brown, blue, red, hypopigmented | **Discoloration: brown, blue, red, hypopigmented | ||
+ | **A tattoo is an artificial papule | ||
*Large macules (~> 2cm) are called "patches" | *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://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 | *http://courses.washington.edu/hubio567/lang/odlnd038.gif | ||
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=====Papule / Plaque===== | =====Papule / Plaque===== | ||
- | *Elevated, solid, 0.5-1 cm diameter | + | *'''Elevated''', solid, 0.5-1 cm diameter |
*Larger is a plaque | *Larger is a plaque | ||
*Confluent papules are called "plaques" | *Confluent papules are called "plaques" | ||
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=====Wheal===== | =====Wheal===== | ||
- | *Firm, edematous plaque | + | *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 | *Wheals are transient, may only last hours | ||
*http://www.skincareguide.ca/images/glossary/wheal.jpg | *http://www.skincareguide.ca/images/glossary/wheal.jpg | ||
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=====Vesicle / Bulla===== | =====Vesicle / Bulla===== | ||
*Circumscribed collection of free fluid up to 0.5 cm diameter | *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 | *Bulla is over 0.5 cm diamter | ||
+ | **Look differently depending on where the fluid resides: under the stratum corneum or under the whole epidermis | ||
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====Secondary Lesions==== | ====Secondary Lesions==== | ||
+ | *Lesions that evolve from pt interaction with a disease process: scratching, picking, et cetera | ||
=====Scales===== | =====Scales===== | ||
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*http://www.steadyhealth.com/2996/Image/copy-of-psoriasis.jpg | *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) | *Crust: collection of dried serum and cellular debris (a scab) | ||
**http://www.dermweb.com/morphology/graphics/morph061.jpg | **http://www.dermweb.com/morphology/graphics/morph061.jpg | ||
**http://www.accessemergencymedicine.com/loadBinary.aspx?fileName=wolf6_c011f019t.jpg | **http://www.accessemergencymedicine.com/loadBinary.aspx?fileName=wolf6_c011f019t.jpg | ||
+ | |||
+ | |||
*Erosion: focal loss of epidermis | *Erosion: focal loss of epidermis | ||
+ | **Any scratch that doesn't scar | ||
**Do not penetrate below the dermal-epidermal junction and thus do not 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 | **http://www.accessmedicine.ca/loadBinary.aspx?name=wolf7&filename=wolf7_c004f010t.jpg | ||
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=====Ulcers===== | =====Ulcers===== | ||
- | *A focal loss of epidermis | + | *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-2.jpg | ||
*http://trialx.com/curetalk/wp-content/blogs.dir/7/files/2011/05/diseases/Skin_Ulcer-3.jpg | *http://trialx.com/curetalk/wp-content/blogs.dir/7/files/2011/05/diseases/Skin_Ulcer-3.jpg | ||
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=====Fissure===== | =====Fissure===== | ||
*Linear loss of epidermis and dermis with sharply defined, vertical walls | *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://www.infoderm.com/infoderm/images/las/lesions/Fissure.jpg | ||
*http://faculty.washington.edu/alexbert/MEDEX/Derm/fisure.gif | *http://faculty.washington.edu/alexbert/MEDEX/Derm/fisure.gif | ||
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=====Atrophy===== | =====Atrophy===== | ||
*Depression in the skin from thinning of the epidermis or dermis | *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://mizzouderm.com/uploads/4/4/2/3/4423869/4212698_orig.jpg?214 | ||
*http://dermimages.med.jhmi.edu/images/Steroid_Atrophy_1_030303.jpg | *http://dermimages.med.jhmi.edu/images/Steroid_Atrophy_1_030303.jpg | ||
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=====Scar===== | =====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. | *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 | *http://www.smartex-balkan.com/wp-content/uploads/2010/09/Keloid-Scar.png | ||
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=====Comedone===== | =====Comedone===== | ||
*Plug of subaceous and keratinaceous debris lodged in the opening of an hair follicle. | *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://acner.org/img/care_and_prevention/blackheads-on-the-neck_3_3552.jpg | ||
*http://www.dartmouth.edu/~thabif/weeklyClinic110600/20GiantComedone.jpg | *http://www.dartmouth.edu/~thabif/weeklyClinic110600/20GiantComedone.jpg | ||
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=====Lichenifcation===== | =====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://missinglink.ucsf.edu/lm/DermatologyGlossary/img/Dermatology%20Glossary/Glossary%20Clinical%20Images/Lichenification-101.jpg | ||
*http://www.skincareguide.ca/images/glossary/lichen_simplex_chronicus.jpg | *http://www.skincareguide.ca/images/glossary/lichen_simplex_chronicus.jpg | ||
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=====Burrow===== | =====Burrow===== | ||
*Narrow, elevated tortuous channel in the skin, created by a parasite | *Narrow, elevated tortuous channel in the skin, created by a parasite | ||
- | *Scabies | + | *Scabies most common |
*http://i.quizlet.net/i/U7z1SI38X8HldKGXBPWjIQ_m.jpg | *http://i.quizlet.net/i/U7z1SI38X8HldKGXBPWjIQ_m.jpg | ||
=====Milia===== | =====Milia===== | ||
*Small cysts under the skin; have walls containing epidermis | *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://dermnetnz.org/doctors/lesions/images/milia1.jpg | ||
*http://www.riversideonline.com/source/images/image_popup/fl7_milia.jpg | *http://www.riversideonline.com/source/images/image_popup/fl7_milia.jpg | ||
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=====Cyst===== | =====Cyst===== | ||
*Circumscribed with wall and lumen; may contain solid matter or fluid | *Circumscribed with wall and lumen; may contain solid matter or fluid | ||
+ | **A larger milia | ||
*http://meded.ucsd.edu/clinicalimg/upper_inclusion_cyst.jpg | *http://meded.ucsd.edu/clinicalimg/upper_inclusion_cyst.jpg | ||
*http://www.primehealthchannel.com/wp-content/uploads/2010/09/Cyst_Profile2.jpg | *http://www.primehealthchannel.com/wp-content/uploads/2010/09/Cyst_Profile2.jpg | ||
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=====Telangiectasia===== | =====Telangiectasia===== | ||
*Dilated superficial blood vessels | *Dilated superficial blood vessels | ||
- | *Also called | + | **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.meddean.luc.edu/lumen/MedEd/medicine/dermatology/melton/cyst2.jpg | ||
*http://www.michmoleremoval.com/sitebuildercontent/sitebuilderpictures/telangiectasia-s.jpg | *http://www.michmoleremoval.com/sitebuildercontent/sitebuilderpictures/telangiectasia-s.jpg | ||
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**http://dermnetnz.org/site-age-specific/img/purpura-s.jpg | **http://dermnetnz.org/site-age-specific/img/purpura-s.jpg | ||
**http://www.skinsite.com/images/batemans%20purpura.gif | **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 |
Revision as of 11:42, 13 October 2011
Contents |
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:
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