Misc skin conditions Flashcards
1
Q
How common is psoriasis? Do genetics and location play a factor?
A
- affects 1-9% of the pop: more prevalent the further away from the equator
- equal incidences in M:F
- hereditary: up to 40% of pts have first degree relative with psoriasis or psoriatic arthritis
2
Q
PP of psoriasis?
A
- normal cell turnover in epidermis takes about 27 days
- cell turnover in psoriasis is reduced to 4 days
- massive increase in number of cells produced and normal cell keratinization doesn’t take place
- subdermal blood vessel dilation also seen (contributes to eryrthema)
- kertatinocytes have shortened cell cycle time of 1.5 days compared to 13 days
- autoimmune component: T lympchocytes and dendritic cells, mult T cells are present in psoriatic lesions, therapies that suppress T cells are very effective
3
Q
Psoriasis RFs?
A
- family hx
- strep infection can trigger guttate psoriasis
- meds: BB, lithium, anti-malaria
- smoking, obesity, and alcohol are assoc
- Vit D deficiency? (greater distance away from equator)
4
Q
Presentation of psoriasis?
A
- bimodal age distribution: early 30-39 yrs late 50-69 yrs - can also occur in kids but less common than in adults - may be gradual onset or sudden - pruritis is common - hx of improvement with sun exposure
5
Q
Assoc conditions of psoriasis?
A
- psoriatic arthritis
- CV disease, malignancy, DM, metabolic syndrome, HTN, IBD, serious infections
- ocular involvement: swollen lids, conjunctivitis, xerosis, uveitis (think autoimmine)
6
Q
Types of psoriasis?
A
- plaque
- inverse
- guttate
- erythrodermic
- pustular
- nails
7
Q
Characteristics of plaque psoriasis?
A
- MC
- 75-80% of cases
- slow-forming
- stable
- usually well defined and symmetrical
- typically appears on knees, scalp, elbows, lower back, and can affect nails
diff from eczema - b/c psoriasis on extensor sides, more scales
8
Q
Plaque psoriasis presentation?
A
- salmon pink papules and plaques, sharply marginated with marked silvery-white scaling
- scales are losse and easily removed by scratching
- removal of scales results in small blood droplets (Auspitz sign)
- plaque at sites of former skin injury (koebner’s phenomenon)
- plaques turn to powder if manipulated, have odor
9
Q
Etiologies of koebner’s phenomenon?
A
- psoriasis plaques that form at site of skin injury
- up to 50% of pts may experience this
- occurs 1-2 wks after injury
may occur from: - bug bites
- bruises and scrapes
- poison ivy or poison oak
- burns, chemical and sunburn
- constant pressure and rubbing, vaccinations, skin blemishes, herpes, chickenpox, acupuncture
10
Q
Distribution of psoriatic lesions?
A
- often symmetrical
- favors elbows, knees, scalp and intertriginous areas
- uncommon on the face
- single lesion or lesions localized to one area or can be over the entire body
11
Q
What is inverse psoriasis?
A
- sharply demarcated plaques
- found in axilla, groin, naval, submammary region, palms, scalp, and soles
- no scales like plaque psoriasis
- more common in overwt pts
- diff to distinguish from candidiasis w/o bx (look for satellite lesions, KOH)
12
Q
What is Guttate psoriasis?
A
- AKA: eruptive psoriasis: has an abrupt onset
- characteristically occurs in young adults and kids: strong assoc b/t recent strep infection (usually pharyngitis) in preceeding 2-3 wks
- mult small teardrop shaped erythematous papules on arms, trunk
- scattered diffusely on proximal extremtities
- usually self limiting in a few weeks to months
13
Q
What is erythrodremic psoriasis?
A
- most generalized: often affects most or all of body’s surface
- erythema and scaling from head to toe: skin looks burnt, sheds in sheets
- inflammatory
- least common
- severe itching and pain as skin reddens and sheds
- HIGH RISK of SYSTEMIC INFECTION and electrolyte imbalances
- need inpt management
14
Q
What is pustular psoriasis?
A
- can be generalized
- severe form with life threatening complications
- acute onset of widespread erythema, scaling and sheets of superficial pustules with erosions characterizes the most severe variant
- can be assoc with malaise, fever, diarrhea, leukocytosis, and hypocalcemia
- a milder form may just affect the fingers
15
Q
What are the most common precipitating factors for erythrodermic and pustular psoriasis?
A
- acute withdrawal of systemic corticosteroids
- can occur in those with other forms of psoriasis but also occurs in pts w/o psoriasis
16
Q
What is nail psoriasis closely assoc to?
A
- psoriatic arthritis
- may appear b/f onset of cutaneous psoriasis
- nails have pitted appearance, may lift up (onycholysis - oil drop sign)
17
Q
Have to distinguish nail psoriasis with subungual hyperkeratosis from what?
A
- from fungal infection
- do KOH
18
Q
General tx guidelines for plaque psoriasis?
A
tx:
exacerbating factors
use both systemic and topical therapy
19
Q
What are some drugs that may exacerbate psoriasis?
Soln to this?
A
- BBs, NSAIDs, lithium, ACEI, digoxin
- consider switching med if possible
- combo therapy for tx is the trend to minimize SEs
20
Q
What are diff types of topical therapies used for plaque psoriasis?
A
- emollients
- steroids
- Vit D analogues
- topical retinoids
- Calcineurin inhibitors
- coal tar preps
- phototherapy: UVA, UVB
21
Q
Use of emollients for tx of psoriasis?
A
- useful in all cases as adjunct
- hydrate stratum corneum
- decrease water evalp.
- soften the scales of the plaques
- some available agents:
Eucerin
Lubriderm
moisturel - lubricating creams are applied 2x daily after bathing, while skin is still damp.
22
Q
Use of topical steroids as tx for psoriasis? How long should they stay on these? Diff preps?
A
- 1st line agent!!
- can be cont. as long as pt has thick active lesions (not worried about long term use causing damage to skin b/c of high turnover rate)
- back off on frequency and strength once better under control
- for thick plaques on extensor surfaces - can use potent preps (betamethasone 0.05% or clobetasol propionate 0.05%)
- often used in conjunction with topical vit D analog, topcial retinoid or UVB therapy
23
Q
Use of vit D analogues? Ex?
A
Calcipotriol (Dovonex):
- causes immune modulation
- used in mild to mod plaque psoriasis
- SEs include hypercalcemia and hypercalciuria when topical doses exceed 100g/wk
- too irritating for face or groin
- may be used as monotherapy with steroids for breakthrough or just a few days a week
24
Q
use of Vit A derivatives (retinoids) in psoriasis tx?
A
Tazarotene (Tazorac):
- modulates differentiation and proliferation of epithelial tissue and exerts some degree of anti-inflammatory and immunological activity
- may cause skin irritation
- effective with little systemic absorption
