Derm Disorders Flashcards
What is atopic dermatitis (eczema)?
Dermatitis, also known as eczema, is a group of diseases that results in inflammation of the skin.[1] These diseases are characterized by itchiness, red skin, and a rash. In cases of short duration there may be small blisters while in long-term cases the skin may become thickened. The area of skin involved can vary from small to the entire body.
Dermatitis is a group of skin conditions that includes atopic dermatitis, allergic contact dermatitis, irritant contact dermatitis, and stasis dermatitis. The exact cause of dermatitis is often unclear. Cases are believed to often involve a combination of irritation, allergy, and poor venous return. The type of dermatitis is generally determined by the person’s history and the location of the rash. For example, irritant dermatitis often occurs on the hands of people who frequently get them wet. Allergic contact dermatitis, however, can occur following brief exposures to substances a person is sensitive to
Where does eczema typically occur?
on the face in infancy and in the antecubital fosse thereafter
What is allergic contact dermatitis?
a type IV hypersensitivity rxn that follows exposure to an antigen.
What is this?
a common melanocytic nevus- aka the common mole. Benign but melanoma can arise in atypical moles
What is Leser-Trelat sign?
the sudden appearance of multiple seborrheic keratoses, indicating an underlying malignancy (e.g. GI or lymphoid)
What is psoriasis?
papules and plaques with silvery scaling, especially on knees and elbows.
What histo characterizes psoriasis?
acanthosis with parakeratotic scaling
increased straum spinosum
decreased stratum granulosum
What is an Auspitz sign?
pinoint bleeding spots from exposure of dermal papillae when scales of psoriasis are scraped off
Impetigo (below) is most commonly due to what?
S. aureus or S. pyogenes. HIGHLY contagious
What is this?
Cellulitis, an acute, extremely painful spreading infection of deeper dermis and subQ tissue
What usually causes cellulitis?
S. aureus or pyogenes
What is this?
Erysipelas, an infection involving the upper dermis and superficial lymphatics, usually from S. pyogenes
Molluscum contagiosum is caused by what?
Poxvirus. Frequently seen in children but sexually transmitted as well
What causes hairy leukoplakia (which cannot be scraped off unlike thrush)?
EBV
What is pemphigus vulgaris?
a potentially fatal autoimmune skin disorder with IgG Abs against desmoglein (a component of desmosomes)
What is happening here?
A Nikolsky sign, splitting of the epidermis in pemphigus vulgaris upon manual stroking of skin
What disease involves IgG Abs against hemidesomosomes?
bullous pemphigoid
Immunoflourescence of bullous pemphigoid showing a linear pattern at the epidermal-dermal junction
What is the difference between stevens-johnson syndrome and toxic epidermal necrolysis (TEN)?
SJS is characterized by fever, bullae formation and necrosis, and sloughing of skin (usually associated with drug AEs) and covering less than 10% of the body while TEN covers 30+%
Actinic keraotsis, a premalignant lesion caused by sun exposure can transform into what?
SCC
Describe BCC
cancer found in sun-exposed areas of the body. Locally invasive, but rarely METs. Presents as pink nodules commonly with telangiectasias, rolled borders, and central crusting
BCC histo with ‘palisading’ nuclei
SCC histo
superficial spreading melanoma
nodular melanoma
lentigo maligna
