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Flashcards in Dermatology Deck (43)
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1
Q

What is the cause of xeroderma pigmentosum?

A

Defective excision repair mechanism for UV damaged DNA (mutation in endonuclease), leads to formation of thymine dimers. Causes extreme sensitivity to light.

2
Q

Leser-Trelat Sign

A

Sudden appearance of multiple seborrheic keratoses. Indicates an underlying malignancy of the GI tract

3
Q

Which skin layer is affected in scalded skin syndrome? (s. aureus)

A

Stratum granulosum

4
Q

Which inflammatory dermatosis has a saw tooth appearance at the dermal-epidermal junction?

What virus can this be associated with?

A

Lichen Planus
Pruritic, purple, polygonal, planar, papules/plaques

Chronic Hep C infection

5
Q

Auspitz Sign

A

Seen in psoriasis
Pinpoint bleeding after picking off the silvery scale (due to elongated dermal papillae and thinning of epidermis above the papillae)

6
Q

What virus is associated with erythema multiforme

A

Herpes Simplex Virus

See targetoid lesions

7
Q

What virus is associated with molluscum contagiosum?

A

Poxvirus

See flesh colored papules that are umbilicated
On histo there are cytoplasmic inclusion bodies

8
Q

Lips and skin cancer

A

“This is a bunch of BS”
Upper lip: basal cell carcinoma (papule with teleangectasia and palisading)
Lower lip: squamous cell carcinoma (nonhealing ulcer, keratin pearls)

9
Q

Sturge Weber Disease

A

Port wine stain on face due to capillary malformations
Ipsilateral leptomeningeal angiomatosis (vascular malformations within the meninges)
Seizures

10
Q

Risk factors for SCC (different from BCC)

A

Arsenic exposure
Immunosuppressive therapy
Chronic inflammation

11
Q

What skin cancer is a patient on immunosuppressive therapy at risk for?

A

Squamous cell carcinoma

12
Q

What is chronic lymphedema a risk factor for?

A

Stewart Treves syndrome - development of cutaneous angiosarcomas

13
Q

What mutation is seen in melanoma? What other disorder is this mutation seen in?

A

Mutation in BRAF (protein kinase) causes proliferation of melanocytes.

Also seen in Hairy Cell Leukemia

14
Q

Cause of albinism

A

due to defect in tyrosine hydroxylase enzyme or tyrosine transport (tyrosine = aromatic amino acid)

15
Q

What skin disorder is associated with celiac disease?

A

Dermatitis herpetiformis

Pruritic blisters on extensor surfaces, IgA deposits, and microabscesses

16
Q

Birbeck granules

A

Seen in Langerhans cells:
dendritic cells of the skin derived from the myeloid cell line that have racquet-shaped intracytoplasmic granules called Birbeck granules

17
Q

Types of exocrine glands

Merocrine

Apocrine

Holocrine

A

Merocrine: cells secrete via exocytosis (ex. Apocrine/eccrine sweat glands, salivary glands)

Apocrine: cells secrete via membrane bound vesicles (ex. Mammary glands)
*vesicles look like apples (apples = breasts)

Holocrine: cell lysis releases entire contents of the cell (ex. Sebaceous glands, meibomian glands)
* release w”hol”e contents of cell

18
Q

What is the cause of male patterned baldness? How do you treat this?

A

Due to excess DHT (dihydrotestosterone)

Treatment is with 5a reductase inhibitors such as Finasteride to reduce the conversion of testosterone to DHT

19
Q

Neurofibromatosis Type 1 vs Type 2

A

Type 1: von Recklinghausen (chromosome 17, “17 letters in von Recklinghausen). Cafe au lait spots, cutaneous neurofibromas, pheos, Lisch nodule (pigmented iris hamartomas)

Type 2: (chromosome 22) Bilateral acousitc schwannomas, juvenile cataracts, meningiomas, ependymomas

20
Q

What is acanthosis nigricans associated with?

A

Insulin resistance

Malignancy (gastric carcinoma)

21
Q

Sandpaper rash

What causes this?

A

Scarlet fever

Erythrogenic toxin

22
Q

Vesicles in different states of healing

A

Varicella Zoster

23
Q

What type of collagen is secreted by the basal keratinocytes?

A

Type VII collagen

24
Q

Nikolsky sign

A

Separation of the epidermis upon manual stroking of the skin

Positive in pemphigus vulgaris (flaccid blisters)
Negative in bullous pemphigus (tense blisters)

25
Q

Destruction of desmosomes

A

Pemphigus vulgaris (fish net immunofluorescence)

IgG

26
Q

Destruction of hemidesmosomes

A

Bullous Pemphigoid (immunofluorescence along basement membrane)

IgG

27
Q

Patient presents with an ulcer above the medial malleolus and a hx of chronic LE edema

A

Stasis dermatitis (common complication of chronic lower edema secondary to venous stasis)

28
Q

Pellagra is due to what?

How does it present?

A

Niacin deficiency causing the 3 D’s:
Diarrhea
Dementia
Dermatitis

*Niacin can be endogenously formed from tryptophan

29
Q

What cytokine is involved in normal wound healing?

A

TGF B

Responsible for fibroblast migration, proliferation, and connective tissue synthesis

30
Q

Strawberry hemangioma

A

Appears in first few weeks of life – will rapidly grow and then will spontaneously regress by age 5-8. DO NOT SURGICALLY REMOVE

31
Q

Xeroderma pigmentosum is caused by a defect in what enzyme?

A

Endonuclease

32
Q

Blueish tender lesion under fingernail

A

Glomus tumor – arises from modified smooth muscle cells of the thermoregulatory glomus body

33
Q

Treatment of psoriasis

A

topical vitamin D analogs (Calcipotiene, calcitriol, and tacalcitol) bind to and activate the vitamin D receptor, a nuclear transcription factor that causes inhibition of keratinocyte proliferation and stimulation of keratinocyte differentiation

Can also use TNF a inhibitors such as Enteracept or Infliximab

34
Q

What is thought to be the cause of atopic dermatitis (eczema) and what will labs show?

A

o Thought to be caused by mutations affecting filaggrin which causes impairment of the skin’s barrier function
o High serum IgE, peripheral eosinophilia, and high levels of cAMP phosphodiesterase in their leukocytes
o At risk of developing allergic rhinitis and asthma

35
Q

What skin layer is increased in psoriasis?

A

Stratum spinosum (Acanthosis)

36
Q

What cell layer has desmosomes?

A

Stratum spinosum

37
Q

What are liver angiosarcomas associated with?

A

Arsenic and vinyl chloride exposure

38
Q

Proteins that make up gap junctions? Function?

A

Connexins

Intercellular communication

39
Q

Proteins that make up tight junctions? Function?

A

Claudins, occludin

Paracellular barrier

40
Q

Proteins that make up adherens junctions? Function?

A

Cadherins

Cellular anchor

41
Q

Proteins that make up desmosomes? Function?

A

Cadherins

Cellular anchor

42
Q

Proteins that make up hemidesmosomes? Function?

A

Integrins

Cellular anchor

43
Q

What happens when there is a defect in cadherin (e-cadherin)

A

Loss of E-cadherin promotes metastasis