Dermatology

Question 1

What is the difference between term and preterm epidermis?

Answer 1

Preterm is half thickness of term -> inc water loss/permeability

Question 2

How is the SA to V ratio in preterm vs term?

Answer 2

Very much increased

Question 3

Why do neonates and esp preterm infants have tendency to blister?

Answer 3

Bc of decreased collagen elastic fibers in dermis -> decreased elasticity, high risk for blisters

Question 4

What is most common pustular rash? What would histology show?

Answer 4

Erythema toxicum, onset 2-3 days

Numerous eosinophils by Wright staining

Question 5

How long can hyperpigmented macular of neonatal pustular melanosis last? What does histology show?

Answer 5

Can last 3 months

Numerous neutrophils by Wright staining pustule

Question 6

What is miliaria?

Answer 6

Heat rash
Trapped sweat, usually intertriginous areas
Miliaria crystalline - no inflammation
Rubra - red papules/pustules
Pustulosa - pustules w red base
Profunda - nonerythematous pustules
Histology: sparse squamous cells and lymphocytes

Question 7

When does neonatal vs infantile acne start?

Answer 7

Neonatal - 3 wks (face and scalp), no treatment

Infantile - 3-4 months (looks more like real acne) may require treatment to prevent scarring

Question 8

What causes bullous impetigo?

Answer 8

Staph aureus
Usually first few days, blisters leaving honey colored crusts
Bullae intraepidermal and constant PMNs

Question 9

What causes staph scalded skin syndrome?

Answer 9

Staph aureus (usually group II phage) exotoxin
Will have positive a Nikolsky sign (epidermis detached by gentle traction)
Starts with bright erythema on face the diffuse bullae (no oral lesions)
Histology: no inflammatory cells
Cx of fluid: sterile (need to cx NP, eye, skin, blood)
Causes no scarring, quick recovery

Question 10

What type of EB is most severe? Least?

Answer 10

Most: Junctional (dermal/epidermal junction), AR, can present with pyloric stenosis. Short life span.
Least: simplex (aka epidermolytic), AD, blisters are infra-epidermal on feet hands scalp, no scarring. Mild.

Also dystrophic: intra-dermal blisters, low type VII collagen, AR and AD types, can cause scarring/infection

Question 11

What is inheritance of Incontinentia pigmenti? Sx?

Answer 11

X linked dominant
Linear inflammatory vesicles along lines of Blaschko, will have whorls on trunks and extremities later in life
*need to evaluate for associated defects (80%, usually CNS, eyes, teeth)
No treatment

Question 12

What are sx of Kaposiform hemangioendothelioma?

Answer 12

Flat, red/purple at birth on trunk/extremities
Does not completely regress
Can cause Kasabach Merritt syndrome
(Consumption syndrome of platelets and then coagulopathy due to large vascular lesions)

Question 13

How common are infantile hemangiomas? Sex predominance? Age?

Answer 13

1-2% of all newborns
More in female
More in preterm infants
40-50% disappear by 5 years, 60-75% by 7 years

Question 14

What is treatment for hemangiomas?

Answer 14

1. Steroids
2. Propranolol
3. Interferon (only if life threatening bc associated with spastic diplegia)

Question 15

Are port wine stains permanent? How often unilateral? Treatment?

Answer 15

Yes, may get deeper in color with adolescence
85% unilateral
Treat with pulsed dye laser (good outcomes)
If involves forehead or periorbital -> need neuro and ophthalmology eval

Question 16

What syndromes have port wine stains?

Answer 16

1. Sturge Weber
2. Klippel Trenaunay Weber
3. Beckwith Weidemann
4. Cobb

Question 17

What is multiple venous malformations suggestive of?

Answer 17

Multiple = blue rubber bleb syndrome

If large lesion, can clot and cause PE (use ppx aspirin)

Question 18

What is cutis marmorata?

Answer 18

Mottling, usually <1 month of age, resolves with warming

• if persists: trisomy 18, 21; Cornelia de Lange, hypothyroid
• if no change w warming: cutis marmorata telangiectatica congenital (venous vascular malformation)

Question 19

How common is Harlequin color change?

Answer 19

10% of newborns, more common in premature
Can occur up to 3-4 wks of age
Usually temp imbalance or autonomic regulatory mechanism of cutaneous vessels

Question 20

What syndromes cause diffuse hypopigmentation?

Answer 20

1. PKU
2. Chediak- Higashi syndrome
3. Albinism and partial albinism
4. Tuberous sclerosis
5. Waardenburg syndrome

Question 21

What is deficiency in albinism? Inheritance?

Answer 21

Tyrosinase, limits melanin production bc tyrosine -> dopamine pathway is blocked
Inheritance: usually AR (partial albinism is AD)

Question 22

What is expected course of Mongolian spot? Pathophysiology?

Answer 22

Fade during 1-2 years, 3% of lesions will persist as adults (most gone by age 6-10)
Pathophys: delayed disappearance of dermal melanocytes

Question 23

What are signs and cause of Xeroderma Pigmentosum?

Answer 23

AR
Decreased DNA repair ability, low endonuclease levels
Skin becomes freckled/a trophic with sun, high risk of cancer. Also with eye photosensitivity
Dx: expose fibroblasts to UV then assess chromosome breakage

Question 24

Mastocytosis

Answer 24

Infiltration of mast cells into skin
Half present in first 2 years, usually good prognosis
Mastrocytoma - most common, first 3 months, 1 or more skin colored/light brown macule
Urticaria pigmentosa: 3-9 months, numerous macules that coalesce on trunk
Diffuse cutaneous mastocytosis: rare, severe. Causes hives after firmly stroking lesion (Darier’s sign) some with HSM, hypotension

Question 25

What is hair collar sign with aplasia cutis and significance?

Answer 25

A long dark hair surrounding the lesion , can be associated with cranial neural tube defects

Question 26

What are sx and Rx for Nevus sebaceous?

Answer 26

0.3% of infants, usually present at birth
Yellow, hairless, waxy plaque usually on scalp
Excision Rec bc 10-15% associated with tumors in adulthood

Question 27

What is epidermal nevus syndrome?

Answer 27

Nevus sebaceous + brain, eye, and skeletal abnormalities

Question 28

X linked ichthyosis

Answer 28

X linked recessive
Large brown scales in first 3 months, does not involve palms/soles/flexure
Secondary to steroid sulfatase deficiency which increases stratum corneum
1/4 males have cryptorchidism, some with cataracts
mothers carriers will have low estradiol and a difficult labor

Question 29

Collodion infant

Answer 29

Thickened stratum corneum, fissures appear after birth and sloughs off 2-3 weeks. Skin beneath red
High risk infection (pna due to aspiration of squamous cells), water loss, hypothermia
60-70% will develop congenital ichthyosiform erythroderma

Question 30

Harlequin icthyosis

Answer 30

Rare, severe, most premature and die
Oral retinoids may improve survival
Thick hardened skin

Question 31

Hypohidrotic ectodermal dysplasia

Answer 31

X linked recessive
Collodion membrane at birth, frontal bossing, depressed nasal bridge, everted lips
Can’t sweat, get fevers, decreased hair. High risk of asthma, eczema, allergies.
Normal cognitive development

Question 32

Leiners syndrome/Nethertons disease

Answer 32

Generalized erythematous desquamative dermatitis with FTT, diarrhea, recurrent infections.
Brittle hair
Associated with complement 5 abnormality

Question 33

When do HSV skin lesions typically appear? What does histology show?

Answer 33

6-13 days of age, usually presenting part (closest to vagina in labor)
Histology: Tzanck smear shows multinucleated giant cells