Inflammatory Dermatoses Path Flashcards
What is “Psoriasis?”
Chronic Inflammatory dermatosis that affects people of all ages. Caused by genetic and environmental factors, multifocal etiology.
What is the genetic association of Psoriasis?
HLA-C, particularly HLA-Cw*0602. However this accounts for only 10% of people with psoriasis.
What immune cells are involved for psoriasis? What do these immune cells cause?
Sensitized CD4 TH1 cells, TH 17 cells, and effector CD8+ T cells all attacking an unknown culprit antigen. They secrete cytokines and growth factors (makes the cytokine soup) that causes keratinocyte proliferation, resulting in the characteristic lesions of psoriasis.
What is the “Koebner Phenomena?”
Psoriasis induced by trauma, resulting in a local inflamm response resulting into the lesion development.
For people with RA, what is the mediator that allows for the development of posriasis?
TNF.
What are some disease states that psoriasis is associated with?
RA, myopathies, enteropathy, spondylitic joint disease, or acquired immunodeficiency syndrome.
Which are the areas that are most commonly affected by psoriasis?
Skin of elbow, knees, scalp, lumbosacral area, intergluteal cleft and glans penis.
Describe the psoriatic lesion?
Well demarcated, pink or salmon colored plaque surrounded by a silver-white adherent scale.
What is “Onycholysis?” How is this related to psoriasis?
Seperation of nail plate from underlying bed, and in psoriasis there will be onycholysis of nails in addition to yellow brown discoloration with pitting, dimpling, thickening and crumbling.
What is the rare variant of psoriasis called when multiple small pustules form on erythematous plaques?
Called “Pustular psoriasis.” Can be benign or life threatening, and in the latter it is associated with fever, leukocytosis, arthralgia, random skin and mucous pustules, secondary infections and electrolyte disturbances.
How does psoriatic lesions present histologically?
Increased cell turnover results in epidermal thickening (acanthosis), with downward elongations of the rete ridges (called “test tubes in a rack” appearance). Stratum granulosum is thin or absent, and extensive overlying parakeratotic scale is seen.
What is the “Auspitz sign?”
Multiple, minute bleeding points when the psoaritic scales are lifted. This is due to the papillae being dilated with blood vessels, and the thinning of the epidermal layer.
What is “Seborrheic Dermatitis?”
A chronic inflammatory dermatosis that involves areas with high density of sebacious glands, such as scalp, forehead (esp glabella), external auditory canal, behind the ear, around the nasal folds and presternal area. It is NOT a disease of the sebacious glands however.
How do the lesions of Seborrheic dermatitis look like?
Macules and papules on a yellow, often greasy base that is due to extensive scaling and crusting.
Although the cause of seborrheic dermatitis isnt known what is suspected?
The lipophilic yeast Malassezia furfur which is associated with tinea versicolor. Also associated with increased sebum production, but not the sole or primary factor
