Skin Pathology Flashcards
Atopic dermatitis
AKA eczema
Skin is xerotic, pruritic, erythematous, often affects flexor creases
Often associated w/ asthma and allergic rhinitis
Familial
Often due to filaggrin mutation –> defective cell envelope formation –> dysfunctional barrier and subsequent inflammation
Psoriasis
Scaly, hyperkeratotic plaques on an eryhtematous background; affects extensor surfaces
Th17 immune dysfunction and keratinocyte hyperplasia w/ reduced transit time
Histologic: parakeratosis (nuclei in cells in the S. corneum)
Tx is immunosuppression
Bullous pemphigoid
Tense, fluid-filled bullae on extremities, axilla, groin
Pruitis may preceed onset of bullae
Onset at age 60+
Autoantibodies attack BP230 and BP180 proteins (type XVII collagens) in hemidesmosomes that attach the S. basale to the lamina densa
Epidermolysis bullosa
Genetic disorder
Skin blisters occur after mild/moderate shearing trauma
Mutated K5 or K14 genes –> weird structure of the keratin heterodimer –> blisters form within the basal keratinocytes
Epidermolytic icthyosis
Genetic disorder
Erythema & blisters from birth through childhood
Late childhood & adulthood characterized by scaling (icthys = fish - fish have scales) in flexor creases
Keratin genes K1 or K10 are mutated
What is filaggrin?
A protein involved in the process of keratin intermediate filament aggregation during the cornification process. After keratin macrofibril aggregation, filaggrin is broken down into molecules that bind water - helps hydrate the S. corneum.
Pemphigus vulgaris
Ab-mediated attack against desmoglein 1 and 3 in desmosomes (type II rxn)
Blisters form within the S. spinosum
Acne vulgaris
Plugged sebaceous ducts that can remain open (blackheads/open comedome) or closed by keratinocytes (whiteheads/closed comedome) –> continued production of sebum –> proliferation of propionibacteria –> inflammation –> rupture down into the dermis –> cystic appearance
Tx: topical retinoids, benzoyl peroxide, salicylic acid
Hidradenitis suppurativa
AKA acne inversa
Recurrent draining abscesses in apocrine gland-rich regions like perineum and axilla
Often involves secondary infection –> rupture into the dermis –> abscess
Tx is surgical removal of the entire area
What is is called when a woman loses hair after childbirth?
Telogen effluvium
What is the fancy term for male pattern baldness?
Androgenic alopecia
Alopecia areata
Lymphocytic attack on antigens at the bulb of hair follicles –> temporary cessation of hair growth
If affects entire scalp it is called alopecia totalis
Entire body = alopecia universalis
Tx is immune suppression
What is your diagnosis?
Onycholysis caused by psoriasis
What is your diagnosis?
Onychomycosis
What’s up wit it?
Paronychia - disruption of the cuticle
What acquired disease is characterized by excessive extracellular matrix deposition, resulting in thickened dermis that can constrict the vasculature in the hands and fingers –> Raynaud’s phenomenon?
Systemic scleroderma
What is your diagnosis?
Gottron’s papules - from dermatomyositis
Describe the biochemical pathways implicated in Type II oculocutaneous albinism and Type III oculucutaneous albinism.
Type II: defective tyrosinase enzyme.
Type III: defective TRP-1/P-protein.
Your 65 year old patient presents with a xerotic, erythematous rash with diffuse fissuring on her lower legs as seen in the photo. What is your diagnosis and how do you treat it?
Stasis dermatitis. Treat with elevation, compression wraps, and corticosteroids (class III cream).
What is your Dx?
Follicular eczema
What is this called?
Longitudinal melanonychia - harmless
What are the spots called?
Dermatosis papulosa nigrans
What are these conditions called?
Nevus of ota (left)
Nevus of ito (right)
