Dermatology Flashcards
What is the cause of xeroderma pigmentosum?
Defective excision repair mechanism for UV damaged DNA (mutation in endonuclease), leads to formation of thymine dimers. Causes extreme sensitivity to light.
Leser-Trelat Sign
Sudden appearance of multiple seborrheic keratoses. Indicates an underlying malignancy of the GI tract
Which skin layer is affected in scalded skin syndrome? (s. aureus)
Stratum granulosum
Which inflammatory dermatosis has a saw tooth appearance at the dermal-epidermal junction?
What virus can this be associated with?
Lichen Planus
Pruritic, purple, polygonal, planar, papules/plaques
Chronic Hep C infection
Auspitz Sign
Seen in psoriasis
Pinpoint bleeding after picking off the silvery scale (due to elongated dermal papillae and thinning of epidermis above the papillae)
What virus is associated with erythema multiforme
Herpes Simplex Virus
See targetoid lesions
What virus is associated with molluscum contagiosum?
Poxvirus
See flesh colored papules that are umbilicated
On histo there are cytoplasmic inclusion bodies
Lips and skin cancer
“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)
Sturge Weber Disease
Port wine stain on face due to capillary malformations
Ipsilateral leptomeningeal angiomatosis (vascular malformations within the meninges)
Seizures
Risk factors for SCC (different from BCC)
Arsenic exposure
Immunosuppressive therapy
Chronic inflammation
What skin cancer is a patient on immunosuppressive therapy at risk for?
Squamous cell carcinoma
What is chronic lymphedema a risk factor for?
Stewart Treves syndrome - development of cutaneous angiosarcomas
What mutation is seen in melanoma? What other disorder is this mutation seen in?
Mutation in BRAF (protein kinase) causes proliferation of melanocytes.
Also seen in Hairy Cell Leukemia
Cause of albinism
due to defect in tyrosine hydroxylase enzyme or tyrosine transport (tyrosine = aromatic amino acid)
What skin disorder is associated with celiac disease?
Dermatitis herpetiformis
Pruritic blisters on extensor surfaces, IgA deposits, and microabscesses
Birbeck granules
Seen in Langerhans cells:
dendritic cells of the skin derived from the myeloid cell line that have racquet-shaped intracytoplasmic granules called Birbeck granules
Types of exocrine glands
Merocrine
Apocrine
Holocrine
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