Skin Development

Question 1

How do you get Piebaldism? What are the clinical features?

Answer 1

• autosomal dominant, mutation in the KIT proto-oncogene
• Impaired migration of melanocytes
• clinical:
  
  • depigmented patches (congenital-present at birth) often with speckles within
  • stable, nonprogressive (remember vitiligo is progressive)
  • white forelock typical

Question 2

How do you distinguish vitiligo from piebaldism?

Answer 2

History! Piebaldism is congenital and vitiligo is not

Question 3

What causes Waardenburg Syndrome and what is associated with it?

Answer 3

• rare disease, mutliple genes implicated in abnormal development of melanocytes
• achromia (a white patch of hair or skin) with other features
  
  • deafness
  • heterochromia irides (eyes are 2 colors)
  • dystopia canthorum (wide distance between eyes)

Question 4

What is port-wine stain?

Answer 4

• malformed, ectactic, dilated capillary to venule sized blood vessels. usually called capillary malformation.
• always present at birth, 0.3-0.6% of newborns
• tend to darken and thicken over time
• distributed along V1, V2, V3

Question 5

How are port-wine stains distributed?

Answer 5

V1-ophthalmic branch, may extend to ocular conjuctiva

V2-maxillary branch

V3-mandibular branch, may extend o oral mucosa

Question 6

What is Sturge Weber Syndrome? What are the symptoms?

Answer 6

• most commonly associated port wine stains in the V1 dermatome (port wine stains in this region have other problems hence why its named)
• Neurological
  
  • seizures
  • developmental delay
  • migraine headaches
  • tam track calcifications (calcification of the occipital and/or temporal cortex)
• Ocular findings
  
  • congenital glaucoma
  • increase choroidal vascularity (tomato ketchup spot)

Question 7

WHat is infantile hemangioma?

Answer 7

most common vascular tumor, 4-5%

composed of proliferating endothelial-like cells that become clinically visible in the first months of life

Question 8

Describe the Infantile Hemangioma growht cycle

Answer 8

• at bith: white flat patch with fine pink-red vessels. pallor due to vasoconstriction
• 1-2 wks: proliferation begins
• growth pahse: variable, 3-9month
• then slowly involutes

Question 9

What is the difference between involution and resolution?

Answer 9

involution is when a scar forms bc its too big, otherwise it resolves

Question 10

What is PHACE syndrome

Answer 10

• P: Posterior fossa abnrmalities
• H: hemangioma (segmental)
• A: Arterial Anomalies
• C: Cardiac Anomalies
• E: Eye anomalies
• S: Sternal clefting/ supraumbilical raphe

Question 11

WHat is the significane of ectodermal dyspasia

Answer 11

• over 150 rare syndromes have alterations in 2 or more structures that derive from the embryonic ectoderm
  
  • developmental defects in hair, teeth, nails, sweat glands, and the lends of the eye

Question 12

What is the pathogenesis of Hypohidrotic ectodermal dysplasia?

Answer 12

• most often X-linked recessive (most patients are males)
• most common Ectodermal dysplasia
• Ectodermal signaling pathway
  
  • ectodysplasin-A1 (EDA-A1)
  • EDA-A1 receptor (EDAR)
  • EDAR associated death domain (EDARADD)

Question 13

What are the clinical features of HED?

Answer 13

• square forehead with frontal bossing
• flattened nasal bridge
• low-lying ears
• skin is thin and dry
• sparse hair
• hypo-anodonthia/peg teeth
• decreased ability to sweat

Question 14

WHat are the recommendations for HED?

Answer 14

avoid overheating

consult dentistry

recommend families ocntact National Foundation for Ectodermal Dysplasias

Question 15

Epidermis and Epidermal derivatives originate from ___________

Answer 15

surface ectoderm

Question 16

where are melanocytes derived from

Answer 16

neural crest

Question 17

where are Langerhans cells derived from?

Answer 17

bone marrow

Question 18

Where are Merkel cells derived from?

Answer 18

epidermal stem cells in the basal layer

Question 19

melanocytes, Langerhans and merkel cells enter and reside in what layer?

Answer 19

epidermis

Question 20

Where is the dermis derived from?

Answer 20

mesenchyme of regional origin

Question 21

During skin development what cross-signaling is essential?

Answer 21

during skin development, ectoderm-menchyme cross-signaling is essential

Question 22

What protects the skin from amniotic fluid?

Answer 22

the vernix caseosa protects the skin from amniotic fluid

Question 23

where are hair follicles, sweat glands and nails derived from?

Answer 23

eidermal buds that extend into the forming dermis

Question 24

what happens to the initial downy lanugo hair that is present at birth?

Answer 24

it is replaced near birth by course hair

Question 25

What are nails derived from?

Answer 25

epidermal thickenings at the tips of the digits

Question 26

What is Piebaldism due to?

Answer 26

an absence of melanocytes in affected skin and hair follicles

Question 27

what are the features of waardenburg syndrome?

Answer 27

white patches of hair or skin with deafness, heterochromia irides and dystopia canthorum

Question 28

Capillary malformations (port wine stains) in the V1 distribution can be associated with \_\_\_\_\_\_\_\_\_

Answer 28

seizures and glaucoma in sturge-weber syndrome

Question 29

Infantile hemangiomas are\_\_\_\_\_\_ with a growth phase followed by \_\_\_\_\_\_

Answer 29

infantile hemangiomas are dynamic, with a growth phase followed by involution

Question 30

Patient with ________ have impaires ability to sweat and overheat