Ch. 24: Skin: Anatomy and Epidermal Diseases Flashcards
What layer of the epidermis is most affected by ichthyosiform dermatoses?
Stratum Corneum gets markedly thickened
(icythyosis=fish-like scales)
What are three general defects involved in ichthyoses?
Increased cell cohesiveness, abnormal keratinization, increased basal cell proliferation
“J” presents with an abnormal patch of leathery, brown skin after admitting to repeatedly scratching the area when he feels anxious after watching the Red Sox lose. Your biopsy revels an area of thickened epidermis (nucleated and enucleated layers), hyperkaeratosis, and dermal fibrosis. What is the diagnosis?
Lichen simplex chronicus
(Key point: this condition causes the nucleated epidermal layers and stratum corneum to thicken, whereas ichthyosiforms cause ONLY STRATUM CORNEUM.
The most common ichthyosis, presents with small white scales on extensor surfaces of extremities, trunk and face.
Ichthyosis Vulgaris
Is ichythosis vulgaris due to environmental exposure, an autoimmune disorder, or a genetic disorder?
What protein is decreased or absent?
Genetic (autosomal dominant)
Defect in synthesis of profilaggrin (keratin filament); very thin granular layer
Which ichthyosis is due to an absence of steroid sulfatase?
X-linked ichthyosis
(granular layer is preserved)
Your 1 week old patient presents with dark blistering, fish-scale-like skin. You quickly recognize epidermolytic hyperkeratosis because you’re that brilliant. To confirm, what distinctive characteristic would you see on pathology slides?
Whorled tonofilaments around the nucleus with a thickened stratum corneum
(Disease due to abonormal keratin synthesis)
Which dermatological condition which is associated with neuropsychiatric problems, presents with warty papules due to an ATP2A2 calcium pump defect?
Darier disease/keratosis follicularis
You got a 280 on Step 1 so you become a dermatologist. Your first patient comes in complaining of scaly plaques on her elbows and knees. The lesions have silvery edges, and if she itches them her skin bleeds in pinpoint locations. You say, “Any MS2 could make this diagnosis!”
What does she have?
Psoriasis
Caused by excessive proliferation of keratinocytes
In psoriasis pathogensis, defective epidermal cell surface receptors lead to a decrease in what molecule?
cAMP
Causes an increase in protein kinases and polyamines, causing a growth-factor like effect for the epidermis
What type of microcirculatory change is common in psoriasis?
Capillary loops of dermal papillae become venules.
When a psoriatic patient’s capillaries become venualized, which immune cells get recruited to the overlying epidermis?
Neutrophils
(Collect in stratum corneum and throughout the epidermis)
What is parakertatosis?
Persistance of nuclei in stratum corneum cells (found in psoriasis)
On histological examination, what might you notice about the venules of a dermal papillae below a psoriatic lesion?
What might you notice about the granular layer?
They become tortuous and dilated
It becomes hypogranulized. (Due to fast cell turnover)
What is a common side-effect of psoriasis that could be mistaken for an autoimmune disorder?
Psoriatic, seronegative, arthritis
What is the common abbreviation for phototherapy after administration of psoralens (compounds that absorb UV light and bind DNA) used in psoriasis treatment?
PUVA
(damage cells to stop over-proliferation)
Mr. Soprano, a 45 y/o male comes to your primary care office with large blisters on his scalp and the inside of his lip. The blisters rupture easily and leave behind a crust. The biopsy comes back like the image below. What does Mr. Soprano have?
Pemphigus vulgaris
(intraepidermal blister)
Mr. Soprano wants to know if his pemphigus vulgaris is a sign he is being poisoned by the Mafia. You tell him to fuhgeddaboudit, because PV is caused by….?
IgG antibodies to keratinocytes, specifically demoglein 3
(autoimmune disease)
When antibodies in PV bind to the self-antigen, what proteinase is released, causing dyshesion between cells?
Plasmin
Which layers of skin separate in pemphigus vulgaris?
The outer epidermal layers from the epidermal basal layer.
What disorder is associated with “tombstone cells” seen in histology, due to epidermal basal cells that remain adherent to the basement membrane?
Pemphigus vulgaris
What are 2 major differences between pemphigus vulgaris and pemphigus foliaceus?
PF has dyshesion between the outer stratum spinosum and stratum granulosum; and has IgG antibodies to desmoglein 1.
PV has dyshesion between the stratum spinosum and the stratum basalis, and has IgG antibodies to desmoglein 3.
What structure separates the dermis from the epidermis?
Basement membrane
What cell makes up the majority of the epidermis?
Keratinocyte
Which layer of the epidermis is the stem cell layer?
Stratum basale
Which structures connect cells in the stratum spinosum?
Desmosomes
(Connections make cells look like they have spine)
Which cell layer has granules in the cells and is between the stratum spinosum and stratum corneum?
Stratum granulosum
What is distinctive about the cells in the epidermal stratum corneum layer?
They have lost their nuclei
Name 4 skin structures ONLY found in the dermis?
Hair shafts, blood vessels, sweat glands, and sebaceous glands
Which cells are responsible for skin color?
Melanocytes
Which skin cells are antigen-presenting cells?
What is the name of their specialized organelles that resemble tennis rackets?
Langerhans cells
Birbeck granules
Which type of collagen in the basement membrane is important in the dermal-epidermal junction?
Type IV
Which dermal layer is sometimes jointly affected in epidermal disease and superficial vascular bed disorders?
Papillary dermis
Which layer of dermis, when disordered, reacts as a part of systemic disease?
Reticular dermis
What would be found in a patient with alopecia areata?
Loss of hair in a circumscribed area, usually on the scalp.
What type of environmental factors have been implicated in psoriasis?
Trauma (major), also drugs, infection, and photosensitivity
What is ancantholysis?
What epidermal disease is it commonly seen in?
Loss of intercellular connections between cells, resulting in loss of cohesion between keratinocytes.
Pemphigus vulgaris
What is the dermatologic term for epidermal hyperplasia?
Acanthosis
