5) Psoriasis Flashcards
What causes psoriasis and how is it characterized?
There is an increase in cell proliferation.
It is characterized by erythema and elevated scaly plaque.
What are the two distinct peaks when psoriasis can occur?
At age 16-22 (early onset)
At age 57-60 (late onset)
Is psoriasis more severe with early onset or late onset?
Early onset has a higher likelihood of being more severe and extensive.
What is the prevalence in women to men
Affects men and women equally.
Is their a genetic risk factor with psoriasis?
Risk ranges from 35-90% if a family history is present but it is more commonly occurring in certain ethnic groups (rarely South/North Americans and Japanese)
What is the formula resulting in an autoimmune disease calculating the etiology of psoriasis?
Genetic predisposition +/- predisposing factor + precipitating trigger
= inappropriate immune response
What are 5 external predisposing factors?
Obesity Alcohol consumption Smoking Stress Viral/bacterial infection
What are the 4 infections that can possible cause a flare in psoriasis?
HIV Thrush Strep throat Staphylococcal skin infection Viral upper respiratory infections
What are three associated triggers to psoriasis?
Drugs (NSAIDs, Beta blockers, lithium)
Cold, dry weather
Skin Trauma (cuts, bruises, burns)
WhT is the Koebner Phenomenon?
Within 7-14 days of experiencing some sort of trauma to the skin (burn, chafing, cut, allergic reaction), psoriasis will follow the trauma.
Occurs in 50% of people who already have psoriasis.
What are the physiological roles of skin?
Wound repairing, thermo-regulating barrier to the elements and pathogens
Protects from UV rays and synthesizes vitamin D.
What are the 3 layers of the skin?
Epidermis (physical barrier)
Dermis (connective tissue and blood vessels)
Hypo-dermis (structure)
How often does the skin renew itself?
Every 4 to 6 weeks
What is the outermost layer of the epidermis called and what is it mainly made up of?
Stratum corneum is mainly composed of keratinocytes.
What are the four types of cells within the epidermis, their roles and the percentage the make up?
Keratinocytes: structure, 80-85%
Melanocytes: pigment, 5%
Langerhans: detection and destruction of foreign bodies, 2-5%
Merkel cells: touch, 6-10%
When do keratinocytes differentiate?
The differentiate while en route from the basal cells to the stratum corneum.
What is the current hypothesis as to what triggers the T-cell mediated, autoimmune disease?
An unknown pathogen stimulates an immune response which leads to the impaired differentiation and hyper-proliferation of keratinocytes
The activation of T-cells on the skin due to antigen presenting cells causes the release of what?
Inflammatory mediators that drive inflammatory response such as cytokines and chemokines
Keratinocyte proliferation causing reduced differentiation and plaque build up is induced by what?
Activated T-cells.
If the normal maturation of a cell is greater than 30 days, what is the abnormal maturation?
3-5 days
How much more keratinocytes does plaque have compared to regular skin?
30x more
What are the 4 major pathogenic changes with psoriasis?
Epidermal thickening
Erythema (development of new blood vessels and increased capillary permeability)
Silvery psoriatic scales
Elongated “rete ridges”
Name the 6 types of psoriasis.
Psoriasis vulgaris (chronic plaque) Guttate Flexural Erythrodermic Pustular Local forms (palmoplantar, scalp, nail)
What are the characteristics of Guttate psoriasis?
Infections or stress can bring on small teardrop lesions on the trunk, limb or face of small children and young adults, that generally clear up on its own.
