Skin Development Flashcards
How do you get Piebaldism? What are the clinical features?
- 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
How do you distinguish vitiligo from piebaldism?
History! Piebaldism is congenital and vitiligo is not
What causes Waardenburg Syndrome and what is associated with it?
- 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)
What is port-wine stain?
- 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
How are port-wine stains distributed?
V1-ophthalmic branch, may extend to ocular conjuctiva
V2-maxillary branch
V3-mandibular branch, may extend o oral mucosa
What is Sturge Weber Syndrome? What are the symptoms?
- 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)
WHat is infantile hemangioma?
most common vascular tumor, 4-5%
composed of proliferating endothelial-like cells that become clinically visible in the first months of life
Describe the Infantile Hemangioma growht cycle
- 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
What is the difference between involution and resolution?
involution is when a scar forms bc its too big, otherwise it resolves
What is PHACE syndrome
- P: Posterior fossa abnrmalities
- H: hemangioma (segmental)
- A: Arterial Anomalies
- C: Cardiac Anomalies
- E: Eye anomalies
- S: Sternal clefting/ supraumbilical raphe
WHat is the significane of ectodermal dyspasia
- 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
What is the pathogenesis of Hypohidrotic ectodermal dysplasia?
- 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)
What are the clinical features of HED?
- 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
WHat are the recommendations for HED?
avoid overheating
consult dentistry
recommend families ocntact National Foundation for Ectodermal Dysplasias
Epidermis and Epidermal derivatives originate from ___________
surface ectoderm
where are melanocytes derived from
neural crest
where are Langerhans cells derived from?
bone marrow
Where are Merkel cells derived from?
epidermal stem cells in the basal layer
melanocytes, Langerhans and merkel cells enter and reside in what layer?
epidermis
Where is the dermis derived from?
mesenchyme of regional origin
During skin development what cross-signaling is essential?
during skin development, ectoderm-menchyme cross-signaling is essential
What protects the skin from amniotic fluid?
the vernix caseosa protects the skin from amniotic fluid
where are hair follicles, sweat glands and nails derived from?
eidermal buds that extend into the forming dermis
what happens to the initial downy lanugo hair that is present at birth?
it is replaced near birth by course hair
What are nails derived from?
epidermal thickenings at the tips of the digits
What is Piebaldism due to?
an absence of melanocytes in affected skin and hair follicles
what are the features of waardenburg syndrome?
white patches of hair or skin with deafness, heterochromia irides and dystopia canthorum
Capillary malformations (port wine stains) in the V1 distribution can be associated with _________
seizures and glaucoma in sturge-weber syndrome
Infantile hemangiomas are______ with a growth phase followed by ______
infantile hemangiomas are dynamic, with a growth phase followed by involution
Patient with ________ have impaires ability to sweat and overheat
