CM: Scaling Disorders Flashcards
What is scale, nummular, pityriasis, and guttate?
scale = pieces of stratum corneum nummular = coin-shaped pityriasis = bran-like guttate = shaped like drops
What causes scaling?
abnormal keratinization: increased proliferation of basal keratinocytes, abnormal maturation, or increased retention of corneocytes
What is parakeratosis?
nucleated stratum corneum cells - indicates incrased proliferation of basal keratinocytes and incomplete keratinization
What causes psoriasis?
autoimmune w inappropriate activation of immune cells (dendritic and T cells) and cytokines that cause keratinocyte activation and proliferation
What is seen on histology in psoriasis?
inflammatory cells in epidermis and dermis accumulation of neutrophils in epidermis increased mitosis of keratinocytes thickening of epidermis = acanthosis parakeratosis absence or shrunken granular layer
What parts of the body does psoriasis have a predilection for?
scalp, extensor limbs, elbows, knees, shins, sacral region, palms, soles, nails
What are the different clinical patterns of psoriasis?
plaque type = classic, most common
guttate type, inverse (axilla and gluteal cleft), erythrodermic, pustular (often palms or soles)
What are big diagnostic clues for psoriasis?
koebner phenomenon
nail involvement - pits, oil-drop changes, onycholysis
arthritis - often symmetric
How long after primary inf does the secondary stage of syphilis appear?
6-8 wks
What is seen on histology in the secondary stage of syph?
epidermal hyperkeratosis
dermis - perivascular infiltrate of monocytes, lymphocytes and *plasma cells
dilation and proliferation of capillaries
silver stain shows spirochetes
What is the clinical manifestation of the secondary stage of syph?
brown-red macules or papules on trunk and extremities - frequently palms and soles
can also manifest as vesicles or pustules or mucous patches (condyloma lata) - mimics lots of stuff
can have diffuse hair loss, inc lateral 1/3 of eyebrow
What is the histology of seborrheic dermatitis?
focal parakeratosis at edges of follicular ostia
often some spongiosis with modest neutrophilic infiltrate
psoriasiform dermatitis
Which parts of the body does seborrheic dermatitis have a predilection for?
scalp, eyebrows, eyelids, nasolabial folds, ears, sternal area, axillae, sub mammary folds, umbilicus, groin, gluteal creases = areas with a lot of sebum
What are the different clinical patterns of seborrheic dermatitis?
classic = greasy yellowish scale on face, dandruff of scalp
infantile - scalp!
sebopsoriasis - mixed features, esp on scalp
erythroderma
immunosuppressed pts - resistant to tx
What is the cause of pityriasis rosa?
maybe HHV-6 or HHV-7 but unknown
What is the histology of pityriasis rosa?
nonspecific
parakeratosis containing serum
focal spongiotic dermatitis pattern w superficial perivascular lymphocytic infiltrate
What is the clinical manifestation of pityriasis rosa?
starts w herald patch on trunk followed by crops of smaller round to oval salmon-colored patches following lines of christmas tree pattern, peripherally attached thin scales, self limited
What is the cause of pityriasis lichenoides?
T-cell lymphoproliferative disorder, trigger unclear
What is the histology of pityriasis lichenoides?
epidermis w parakeratosis and spongiosis, keratinocyte necrosis, erythrocytes in epidermis
wedge shaped inflammatory infiltrate in dermis
What is the clinical manifestation of pityriasis lichenoides?
acute = bright red edematous papules, may erode or ulcerate chronic = red-brown lesion w scale, post inflammatory hyperpigmentation
What is the cause of lichen planus?
T-cell lymphoproliferative disorder, trigger unclear
What is the histology of lichen planus?
epidermis: hyperkeratosis w irregular acanthosis, focal hypergranulosis, civatte or colloid bodies (round or ovoid, eosinophilic deposits in lower epidermis or upper dermis)
dermis - band like lymphocytes along dermal epidermal jxn, pigment incontinence, loss of melanin from basal cells w accumulation of melanin in upper dermis
What is the clinical manifestation of lichen planus?
flat topped, polygonal violaceous papules that can coalesce into plaques, Koebnerization
the P’s: purple, polygonal, pruritic*, papules
can have fine white lines = Wickham striae - wrists, pretibial area, mucous membranes
*oral lesions, nail involvement
What is the cause of lichen simplex chronicus?
persistent rubbing or scratching results in contemporary hyperplasia
