Skin Disorders B&B Flashcards
acne is inflammation of _____ glands
sebaceous
Acne is due to high Androgens
comedones
sebaceous ducts blocked by debris (excess keratin and sebum)
creates lipid-rich environment for bacteria to grow —> acne
open comedo = blackhead
closed comedo = whitehead (covered by skin)
what is the clinical use of topical benzoyl peroxide?
treats acne by breaking down keratin to unblock pores (comedolytic)
also bactericidal to propionibacterium acnes
which 2 antibiotics are typically used to treat acne?
clindamycin and erythromycin
bactericidal to propionibacterium acnes
how does isotretinoin (accutane) treat acne?
aka 13-cis-retinoic acid (vitamin A derivative)
binds nuclear receptors RAR (retinoic acid) and RXR (retinoid X)
this causes a decrease in keratin production —> less follicular occlusion
highly teratogenic (requires pregnancy test prior to taking)
seborrheic dermatitis - cause and treatment
red plaques with scale (flaky skin) on face and scalp - areas with lots of sebaceous glands
poorly understood but associated with fungal infection by Malassezia - treat with antifungals and corticosteroids
Patient is a 34yo M presenting to their dermatologist with a new dark brown pigmented lesion of uniform color. It is round and about 3mm wide. What is it most likely?
acquired (vs congenital) melanocytic nevus (mole): benign neoplasm of melanocytes
usually >6mm, uniform color, round/oval
bigger than 6mm or non-uniform color is suspicious for melanoma, rarely develop dysplasia/melanoma over time
junctional vs compound vs intradermal nevi
nevus = mole, due to overgrowth of melanocytes
junctional nevi: melanocyte growth along dermal-epidermal junction, common in children
compound nevi: melanocyte growth in epidermis and dermis
intradermal nevi: loss of junctional lesion, melanocyte growth only in dermis, common in adults
pseudofolliculitis barbae
aka razor/shave bumps, inflammation from trapped hairs
form firm papules/pustules, most often in black men
how and where does psoriasis appear?
chronic inflammatory skin disorder of well-demarcated plaques that are pink/salmon colored with silver-white scaling
most commonly on extensor surfaces - knees and elbows
which genes are associated with development of psoriasis?
believed to be autoimmune, associated with HLA-C (human leukocyte antigen)
what are the classic histological findings of psoriasis? (5)
- acanthosis: thickening of epidermis
- parakeratotic scaling: retained nuclei in stratum corneum, indicates hyperproliferation
- munro microabscesses: neutrophils in stratum corneum
- thickened stratum spinosum
- thinned/absent stratum granulosum
Auspitz sign is a positive indication of which skin disorder?
Auspitz sign: bleeding when a scale breaks in a patient with psoriasis
indicates the dermis blood vessels are very close to the epidermis surface
this also allows for neutrophils to migrate towards the surface in the epidermis (munro microabscesses)
what symptoms with patients with psoriasis develop outside of skin plaques? (2)
- nail pitting or onycholysis (separation of nail from nail bed)
- psoriatic arthritis: seronegative spondyloarthritis
which patients does rosacea most often affect?
adults >30 who are light-skinned, greatest risk in Celtics and Northern Europeans
inflammatory skin condition, chronic redness of nose/cheeks
what are the clinical features and appearance of rosacea? (3)
inflammatory skin condition in light-skinned adults
- chronic redness of nose and cheeks
- facial flushing (triggered by alcohol, temperature, spicy foods, etc)
- phymatous rosacea: skin hypertrophy most often on nose (rhinophyma)
seborrheic keratosis is caused by proliferation of _____
common benign tumors caused by proliferation of immature keratinocytes
spontaneously occur in older patients (50+), common on trunk
flat, well-demarcated, round/oval, dark, velvety appearance
Pt is a 71yo F presenting to her GP for an annual checkup. Skin check reveals flat, well-demarcated, round lesions with a dark, velvety appearance on the trunk. These lesions, ______, are caused by proliferation of ______.
seborrheic keratosis: common benign tumors caused by proliferation of immature keratinocytes
spontaneously occur in older patients (50+), common on trunk
flat, well-demarcated, round/oval, dark, velvety appearance
what does biopsy of seborrheic keratosis show?
common benign tumors caused by proliferation of immature keratinocytes, spontaneously occur in older patients (50+), common on trunk
biopsy shows dark immature keratinocytes and “horn cysts” (filled with keratin)
Patient is a 71yo M presenting to their GP with an “explosive onset” of multiple itchy lesions on their back. The lesions appear flat, well-demarcated, round/oval, dark, and velvety. What should you rule out first?
Leser-Trelat sign: explosive onset of multiple itchy seborrheic keratosis lesions (benign tumors caused by proliferation of immature keratinocytes)
probably caused by cytokines, associated with malignancies - most often gastric adenocarcinoma
a positive Leser-Trelat sign is associated with which malignancy?
Leser-Trelat sign: explosive onset of multiple itchy seborrheic keratosis lesions (benign tumors caused by proliferation of immature keratinocytes)
probably caused by cytokines, associated with malignancies - most often gastric adenocarcinoma
what is the cause of verrucae?
verrucae = warts, cellular proliferation caused by HPV
verruca vulgaris = skin, most common
verruca plana = flat wart on skin
condyloma acuminatum = venereal warts
what is the characteristic biopsy finding of verruca vulgaris?
aka cutaneous warts, caused by HPV
verruca vulgaris transmitted via contact with virus - common on hands
causes epidermal hyperplasia and koilocytosis - cytoplasmic clearing around nucleus appears like halos
septal vs lobular panniculitis
panniculitis = inflammation of subcutaneous fat
septal panniculitis: inflammation is in between lobules of fat
lobular panniculitis: inflammation is within lobules of fat
what occurs in erythema nodosum, and what type of hypersensitivity reaction is this?
septal panniculitis: inflammation of septa of fat between dermis and fascia
presents with painful red nodules (it’s in the name) most often on shins
Type IV hypersensitivity
idiopathic or trigged by strep infection, Crohn’s disease (precedes flares), sarcoidosis, coccidiomycosis
Your patient with Crohn’s diseases comes into the office worried they are about to experience a flare. They state that their shins develop red, painful nodules preceding a Crohn’s flare. A tissue sample is taken which shows septal panniculitis. What is the skin condition they are experiencing?
erythema nodosum: septal panniculitis (inflammation of septa of fat between dermis and fascia), presents with painful red nodules (it’s in the name) most often on shins
Type IV hypersensitivity
idiopathic or trigged by strep infection, Crohn’s disease (precedes flares), sarcoidosis, coccidiomycosis
with which virus is lichen planus associated?
intensely itchy purple, flat lesions (arms, legs, wrists, ankles)
associated with Hepatitis C
rare, chronic inflammatory skin disorder of unknown pathogenesis that is associated with Hepatitis C and presents with intensely itchy, purple flat lesions - what is?
lichen planus
what would biopsy of a lichen planus lesion show?
intensely itchy purple lesions, associated with Hepatitis C
histology shows lymphocytes at dermal-epidermal junction, hyperkeratosis, hypergranulosis (thick granular layer), sawtooth pattern of rete ridges
Pt is a 34yo F with PMH significant for Hepatitis C presenting to their GP with complaint of itchy lesions on their wrists and ankles. Exam is also significant for white striations within the mouth mucosa. A biopsy is taken from a lesion, which shows a sawtooth pattern of the rete ridges of the epidermis. What is the diagnosis?
lichen planus: intensely itchy purple/flat lesions, associated with Hepatitis C (pathogenesis unknown)
Wichham striae: white dots/lines seen with mucosal involvement
characteristic histology is hypergranulosis + sawtooth rete ridges
pityriasis rosea
acute/eruptive, self-limited skin rash (resolves 2-3 months, no treatment required) of unknown cause
begins with ”herald patch” (single light red lesion on chest/neck/back) followed by multiple lesions on trunk days later with “Christmas tree distribution” (following dermatomes in diagonal lines going down)
Patient presents to the dermatology clinic with concern of an eruption of light red lesions on their trunk. The patient says the rash began with a single round patch on their chest 3 days prior. They have no allergies and were not in nature recently. The dermatologist decides to monitor the rash without treatment. It fades entirely within 2 months. What was the diagnosis?
pityriasis rosea: acute/eruptive, self-limited skin rash (resolves 2-3 months, no treatment required) of unknown cause
begins with ”herald patch” (single light red lesion on chest/neck/back) followed by multiple lesions on trunk days later with “Christmas tree distribution” (following dermatomes in diagonal lines going down)
partial vs full thickness 2nd degree burns
partial thickness 2nd degree burn: epidermis + some dermis affected, blisters and blanching with pressure
full thickness 2nd degree burn: epidermis + most dermis affected, yellow/white due to disrupted blood flow, heal with scarring
3rd degrees vs 4th degree burn
3rd degree: entire epidermis + dermis
4th degree: entire skin + superficial fat
UVB vs UVA radiation
UVB: wavelength 280-320nm, most effective at causing sunburn
UVA: wavelength 320-400nm
