Verruca Flashcards
What are verruca warts caused by?
HPV
what kind of virus is HPV?
ds DNA virus surrounded by an icosohedral (has 20 sides) capsule
HPV warts are very persistent, what is this attributed to?
lack of Langerhans cells at site of lesion, leading to decreased T-cell response
what type of environment does HPV thrive in to promote infection/
pH of 5 (seen in swimming pools)
do warts have an incubation period? if so, for how long?
4-20 months
verruca warts invade which layer of the skin?
purely epidermal in its histopathology
does not extend into the dermis
what are the 3 pathognomonic characteristics of verruca warts?
- acanthosis
- hyperkeratosis
- papillomatosis
what is acanthosis?
thickening of stratum spinosum
what is hyperkeratosis?
thickening of stratum corneum
what is papillomatosis?
upward proliferation of epidermal papillae causing surface of epidermis to show irregular undulation
in which layer does DNA and protein production occur?
stratum spinosum
in which layer does final virus assembly occur?
granular layer
what are the black dots or petechiae that are seen clinically within the white fibrotic base of the wart due to?
papillomatosis
what are the 3 most common forms of HPV causing plantar warts in humans?
HPV 1 (common wart) HPV 2 (mosaic wart) HPV 4 (common wart) HPV 10 HPV 63- has also been implicated
how can you differentiate between a wart and IPK?
wart will hurt with side-to-side compression whereas an IPK will hurt more on direct compression
where are IPK’s found? how about in comparison to warts? or porokeratosis?
IPK- found on WB areas
warts & porokeratosis - found anywhere on plantar surface
for some verruca, you worry about it undergoing transformation to what?
squamous cell CA
What is the MOA for topical salicylic acid?
keratolytic agent- hastens de-squamation of the skin
What is the MOA of Cantharidin?
is applied under occlusion and causes a severe blister
What is the MOA of liquid nitrogen (cryosurgery)?
cell death occurs below -20C
What is the MOA of liquid nitrogen (cryosurgery)?
cell death occurs below -20C
what is the MOA of topical steroids?
under occlusion, it inhibits cell division and synthesis of DNA in epidermis
what is the MOA of tretinoin (topical Vitamin A)?
increases differentiation and proliferation of epidermis
what is the MOA of 5-FU?
inhibits DNA synthesis
what is systemic etretinate (Soriatane) MOA?
systemic retinoid for psoriasis but can be taken orally to clear warts
what is MOA of Tagamet (cimetidine) ?
interferes with suppressor T-cell function, so inflammatory response against virus is prolonged
what is MOA of 0.1% bleomycin ?
(intralesional injection therapy) - inhibits DNA synthesis
what is the theory behind immunotherapy for treating verruca?
theory is to induce a delayed cutaneous hypersensitivity reaction against the wart
what is MOA of 3% topical SADBE?
induces a delayed hypersensitivity reaction
what is the MOA of Imiquimod (Aldara) cream?
-recruits cytokines and IFN-alpha to induce keratinocytes to produce enzymes to block viral replication
what is the needling technique?
needle is inserted repeatedly into the wart, and works by destruction of tissue and induction of inflammatory response
what is curettage technique?
-margin of wart bluntly dissected with tissue nipper
what is hyfrecation?
electrodessication that uses spark-gap technology and causes tissue dehydration –> cell death ensues with thrombosis of blood vessels
light passed thru a CO2 gas chamber is absorbed by what?
water –> so any tissue that absorbs this will become fried
light passed thru a chamber of dye is absorbed by what?
red pigment –> causes thrombosis of vessels
