Derm II Test 1

Question 1

Lichen Planus

Answer 1

Pruritic inflammatory disease of skin/mucous membranes/hair follicles - affects adults - Immunologic T-Cell mediated reaction - Leads to Keratinocytes undergoing apoptosis.

Lesions = 4 P’s Purple, Polygonal. Prurutic, papule - Grouped together, flexor aspect/lumbar area/eyelids/shins/scalp - may have reticulate white lesion on buccal mucosa

Si/Sx = May be asymptomatic, often pruritic - 2/3 will have lesions for <1 yr - May cause hair loss and nail damage - Variations can ulcer

Dx = Biopsy

Tx = Pot Top Steroids with occlusion or intralesional steroid injection

Question 2

Seborrheic Keratosis

Answer 2

Senile wart, basal cell papilloma - Benign “warty” growth.

Epidemiology = Over 90% of adults >60 Y/O have one or more - Males and females all races - Begin in the 30s - Cause UNK

Presentation = “Stuck on” flat or raised papule or plaque 1-several cm Diameter - White, flesh-coloured to tan, brown, warty or smooth

Tx = none

Question 3

Kaposi Sarcoma

Answer 3

Vascular neoplasm brought on by genetic/hormonal factors, immunodeficiency or infection with HHV 8 - Rare before Aids epidemic

4 Types - Classic: Elderly men of Mediteranean/Middle European/Subsaharan Africa - HIV associated: Mostly MSM (sexual Fecal oral HHV-8) - Endemic/African: Young adults/children - Iatrogenic immune suppressed

Presentation = Red to purplish macules that evolve to infiltrative plaques/nodules or tumors on mucous membranes or skin, often lower extremities much later on arms and hands (HIV associated KS has predilection of head/neck/mucous membranes) - Lymphedema - Initially small/painless become painful/ulcerated - Internal involvement is possible in GI tract/lungs can lead to edema/bleeding/SOB

Histology - Early: Endothelial cells of capillaries are large and protrude into lumen like buds - Later: Proliferation of vessels around preexisting vessels and adnexal structures - Spindle cells found in nodular lesions

Dx = Biopsy

Clin Course = Variable - Progress slowly w/ rare lymph node or visceral involvment - Death usually years later from unrelated cause (Except african type - death w/iin 2 years) - Aids related is almost never fatal

Tx = HIV: Regression associated with overall improvement in immune function (HIV anturetroviral) - Radiation - Cryotherapy - Surgical excision - Topical alitretoin: Binds retinoid receptors inhibiting cell growth - Pulsed dye laser: ablation of local lesions

Question 4

Actinic Keratosis

Answer 4

In-Situ dysplasias due to UV radiation -> may progress to Squamous Cell Carcinoma (SCC) - Thick scale growth (keratosis) caused by sunlight (actinic) - Most common epithelial precancerous lesion

Epidemiology = White>Darker skin - Men>Women - Most common >50, but can be younger - Inc risk with outdoor occupation/lifestyle - Rate in US 11 to 26%

Etiology = UVR leads to mutation (TP53, deletion of gene coding for p16 tumor suppressor protein)

PathpoPhys = Epidermal lesion with atypical keratinocytes at the basal layer that may extend upward to the cornified layers - Epidermis shows cellular atypia/hyperkeratpsis w/inflammatory infiltrate

Clin Man = Found on chronically sun exposed surfaces (face/ears/scalp/dorsal hands/forearms/anterior legs) - Multiple discrete, flat or elevated Verrucous or keratotic, red. pigmented or skin colored - May have scale or be smooth and shiny - On palpation rough “sandpaper” texture - Many times felt easier than seen - 3mm to 2 cm diameter.

Diff = Basal Cell Carcinoma (BCC) - Seborrheic Keratosis (SK is more “Stuck on” appearing with sharper margin) - Squamous Cell Carcinoma (Hypertrophic AK’s can resemble) - Lupus Erythematous (early lesions mimic)

Dx - Usually CLinical/Hx - Biopsy (if palpable dermal component or stretching of skin shows “Pearly” quality, if lesion >6mm or one that has failed w/ appropriate therapy)

Tx = Since some AK progress to SCC treat. - MOdality based on number of lesions, persistence, PT tolerence - Surgical (cryotherapy) - Medical (Imiquimod, 5-FU)

Question 5

Actinic Keratosis: Cryotherapy

Answer 5

Most effective - Liquid Nitrogen applied by cotton tip or spray device - Goal is to lower the Temp of the skin and prodice cell death -320 degree F - Other structures Collagen/blood vessels/nerves are more resistant than Keratinocytes - Risk Blistering, melanocytes more sensative (hypopigmented spot) - May require multiple Tx - Clearance 67-88%

Question 6

Actinic Keratosis - Imiquimod (5% Aldara, 3.75% Zyclara)

Answer 6

For extensive, broad, and numerous lesions - Interferon inducer that produces local immunologic reaction against the lesion - 5% applied 3 x a week for 1 month - 3.75% applied QD for 2 weeks on, 2weeks off for 2 months. - Causes erythema and crusting - Less irritating than 5-FU

Question 7

Actinic Keratosis: Ingebol Mebutate, 5-FU

Answer 7

Ingenol mebutate (Picato) - Induces cell death, apply qd x3 days to face or 2 days to body

5-FU (Efudex) - Intereferes with DNA synthesis apply BID for 4 weeks - Very Irritating

Question 8

Actinic Keratosis: F/U, Prognosis, Prevention

Answer 8

F/U = Areas should smooth over and lesion resolve - Stubborn lesions should be biopsied for SCC concern

Prognosis = Good with monitoring every 2-6 months - Guarded with PT w/ continued significant exposure to sun

Prevention = Avoid sun between 10AM and 4 PM - Use Broad-spectrum sunscreen w/ excellent UVB/UVA coverage - Apply sunscreen at least 20 minutes before going out - Reapply sunscreen every 2 hours or more often if swimming/sweating - Wear sun-protective clothing, a wide-brimmed hat, sunglasses.

Question 9

Nonmelanoma Skin Cancers

Answer 9

Most common cancer - 1 in 2 men, 1 in 3 women in USA will develop NMSC in thier life - Usually after 55 Y/O - Only about 2000-2500 deaths annually (5% of all medicare costs) -

3 years following diagnosis of Initial NMSC 40% develop BCC, 18% of SCC PTs develop another SCC - At 5 year mark 50% women, 70% men will develop second NMSC

Question 10

Basal Cell Carcinoma (BCC)

Answer 10

BCC is an epithelial tumor of the Basal Keratinocytes - Basal Cells invade the dermis, but seldom invade other parts of the body - DNA of certain genes is often damage caused by sun exposure - Most common cancer (2.8 million Americans every year) - 75% NMSC - Slow-growing, rarely metastasize (.0028-.55%) to lymphnodes/lung/bone - Treatable.

Epidemiology/Risk = Lifeteime riskin the white pop 33-39% for men and 23-38% for women - White>Dark skin - Geography (greater risk closer to equater) - Age >40 - Outdoor lifestyle

Etiology/Pathophy = UVR contibutes (natural/tanning booth) - BCC aride from immature pluripotential cells assoc w/ hair follicle Mutations activate pathway that controls cell growth - Mutation also activates oncogenes and inactivates tumor suppressor genes leading to tumor grothw - immunosuppression for organ transplant inc risk of BCC x10

Clin Man = Often PT has HX of sun exposure - Report slowly enlarging lesion (deosn’t heal/bleeds easily) - Occurs mostly on face/head/neck/hands - BCC usually appears as flat/firm/pale area that is small/raised/pink/red/translucent/pearly/waxy and the area may bleed following minor injury, may have “rolled” edge - BCC runs chronic course as lesion slowly enlarge and tends to become more ulcerative “Rodent ulcer” - Bleed without pain/symptoms - May heal spontaneously and form scar tissue - Ulcerative may burrow deep in to the SQ tissues leading to extensive destruction

Varients = Nodular - Most common Waxy/pearly/semitranslucent nodules or papules with “rolled edge” forming around a central deprsiion that may or may not ulver/bleed/crust

Superficial - Appears as a dry scaley lesion, superficial flat growths, may be misdiagbosed as Eczema or peoriasis - Edge shows threadlike raised border

Morpheaform (Sclerosing) - Appear as white sclerotic plaque w/ telangiectasia - scar like in appearance

Pigmented - Similar to nodular, but brown/black pifmentation is present - Most BCE in dark complexioned person (HSipanics/asians) this is what they develop.

Question 11

Basal Cell Carcinoma (BCC): Diff, Dx, Tx

Answer 11

Differential = Scc (biopsy), Sebaceous hyperplasia (not crusty/never bleed), Actinic Keratosis (biopsy), Eczema (may improve with top steroids), Psoriasis (May improve w/ Top Steroids)

Dx = Biopsy (generally consist of large/round or ocal tumor islands w/ dermis often with an epidermal attachement)

Tx = Goal is to permanently cure with best cosmetic result. - Reoccurrence results from inadequate Tx - Usually seen inthe first 4-12 months after Tx

Surgical, Topical, Radiation

Question 12

Basal Cell Carcinoma (BCC): Topical Tx

Answer 12

Best for superficial BCC, less invasive lower cure rate - 5% imiquimod: for Tx of nonfacial superficial BCC that are <2 cm, applied 5 days per week for duration of 6-12 weeks 80% cure rate-

-%FU: is approved for the Tx of superficial BCC, administered BID for 3-6 weeks

Question 13

Basal Cell Carcinoma (BCC): Surgical Tx

Answer 13

Electrodesiccation and Curettage (E&C): For superficial lesion on non-hair bearing areas - Practitioner dependent technique - Uses sharp curette to scrape away the firable tumor tissue until normal firm dermis is felt, area is first electrodesiccation to cause necrosis of cells, debris is then curettetd to the base of the wound and the cycle is repeated two more times if indicated - Relies on the textural differences between tumor cells and the surrounding normal tissue - Cost-effective and rapid to perform, not suitable for treating recurrent tumors, lesions larger than 2cm in diameter, tumors extending into the fat, tumors at sites of high risk for recurrence or lesions with ill-defined borders

Cryosurgery: NOt common - COnsidered for small <2cm, well defined primary BCC - Useful for PTs who are debilitated with medical conditions that preclude other surgery types - Generally not recommended for BCC deeply invasive w/ ulcerated lesions/recurring tumors w/ill-defined borders - Scarring or hypopigmentation may result

Excision with margins: High cure rate 95% - Excision is less effective w/out clearly defined clinical margins and is far less effective in treating recurrent BCC that it is in treating primary BCC - 4to6 mm margin or normal skin is removed

Mohs Micrographic Surgery: Gold Standard - Tumor >2cm - Facial areas - Technique of taking small layer at time and while keeping tissue oriented is processed and examined under a microscope and mapped next layer is then excised sparing healthy tissue - Gives smallest defect ensuring best cosmetic potential

Radiation: Generally used in olde3r PTs who are not candidates for surgery or where surgical excision will be disfiguring - Radiation takes 5 visits to as many as 25 visits for radiation therapy - Cure rates can be as high as 95% for small tumor or as low as 80% for large tumors.

Question 14

Basal Cell Carcinoma (BCC): Prognosis

Answer 14

Prognosis: Good if appropriate method of treatment is used in early primary basal-cell cancers. Recurrent cancers are much harder to cure, with a higher recurrent rate with any methods of treatment - 100% survival if has not metastasized, it grows locally with invasion and destruction of local tissues - the cancer can impinge on the vital structures and if allowed to grow can cause related morbidity and cosmetic disfigurement

Question 15

Squamous Cell Carcinoma

Answer 15

20% NMSC, 700000 case in US annully, 2500 deaths, May arise from Actinic Keratosis, Can metastasize 0.5-5%, Arise from malignant prolif of epidermal Keratinocytes, likelyhood of developing SCC is dependent on exposure to risk factors (UV) and PT-specific char age/skin type/ethnicity

Epidemiolgy/Risk = Older than 50 Y/O - Male> Female - Light > dark skin - Tobacco/alcoho - Geography - Hx of previos NMSC - Immunosuppression - HPV - Chemical Carcinogens

Etiology/Patho = UVR,PUVA, Smoking, HPV(16,18,31,35) Primarily lead to DNA damage - Char by irregular nest of epidermal cells invading dermis to varying degrees - Developmeny of apoptic resistance through functional loss of TP53

Types = SCC in Situ (Bowen’s Disease): Full thickness of epidermis - Invasive: Penetrates into the dermis

Question 16

Squamous Cell Carcinoma - Clin Manifestation

Answer 16

Typically begins at site of AK (face/backs of hands etc) - Lesions may be superficial papules/plaques/nodules discrete and hard arising from an indurated round elevated bases - Over months becomes larger and ulcerated (initially crusted) - On palpation may be hard disk, moveable but overtime can be fixed - invades underlying tissue,

Lower Lip: starts as actinic chelitis - Local thickening on keratosi then firm nodule that may grow outward as sizable tumor - Usually +hx of smoking

Periungual: Presents w/ Si of swelling/erythema/localized pain - Commonly in nailfolds of hands (looks warty)

Question 17

Squamous Cell Carcinoma: Dif, Dx, Prognosi

Answer 17

Diff = AK (Biopsy), Eczematous rash/Atopic Derm (distribution/pruritic/responsive to steroids)

Dx = Biopsy (histologic hallmark of SCC “Keratin Pearls” well formed desmosome attachments and intracytoplasmic bundles of keratin tonofilaments) - +/- Lymphadenopathy on palpation in adjacent lymph nodes

Tx = Excision. Mohs, Radiation

Prognosis = Mohs (94-99% for SCC) - SCC metastasis is generally assoc w/ poor prognosis with a 3-year disease-free survival rate in adult PTs 56% - PTs with in-transit or regional metastasis as thier first site of metastases have better survivalrates than those with distal metastases

F/U = Annuial skin check/ derm referral / Teart AKs

Question 18

Melanoma

Answer 18

Melanocye cancer - Malignant/Cutaneous melanoma - <5% of skin cancers - most deadly

Risk = M (moles:atypical) M (moles: >50 common moles) R (Red hair/freckling) I (Inability to tan) S (Sunburn:severe/blistering) K (Kindred/family Hx)

Etiology = Damage to DNA of melanocyte that promote oncogenes and inhibit Tumor suppresor gene - UVR major factor - Non-inherited BRAF oncogene mutation - Familial inheritance of melanomas have mutation in suppressor genes

Pathophys = Typically originates from melanocytes via dermo-epidermal junction - Almost half will develop in preexisting nevi - Usually, prolonged noninvasive radially oriented growth phase in which lesion enlarges asymmetrically - Tumor nodule develops reflecting a verical growth pjase - greatest risk factor for metastasis is depth of invasion

Question 19

Melanoma: Clin manifestations

Answer 19

May be macular/ nodular - Color varies from white, non-pigmented to dark black, blue or red - Lesions boarders tend tobe irregular - Growth is quick or slow - Distribution can be on non sun exposed areas too

A (Asymmety) B (Border) C (Color) D (Diameter >6mm)

Superficial spreading: Does not have a pref for sun-damaged skin - tendency to multi coloration including black/red/brown/blue.white - Boarders tend to be more sharply defined

Lentigo Meligna: Start as a Macular and flat then become nodular - Most common on sun damaged skin - insidious slow growth

Nodular: Arise w/out apparent radial growth phase - primarily sun-exposed areas of head/neck/trunk - smooth and dome-shaped - friable/ulcerated/bleeding

Acral-Lentiginous: Most common in darker skin - Light Brown/uniform pigmentation initially - on palms/soles/nail beds - Lesions become darker/nodular and may ulcerate - many times there is Dx delay

Question 20

Melanoma: Metastasis, Staging

Answer 20

Metastasis = Early Mtes occur via lymphatics and regional lymphadenopathy may be the first sign - Satellite metastasis appear as pigmented nodules around the site of excision or lesion - Later spread via bloodstream to anywhere (skin/brain/lung/bone/etc)

Staging = T (tumor) how far it has grown in the skin assigned 0-4 based on tumor thickness (depth) (T1 for 1 mm, T2 1-2mm, T3 2-3mm etc)

N (Lymph nodes) assigned 0-3 based on whether melanoma has spread to lymph nodes or in lymphatic channels.

M (metastasize) base which organs and blood levels of LDH

(M0-no metasteses, Stage III if any lymph involvement, Stage IV any Serum involvement)

Question 21

Melanoma: Breslow Thickness

Answer 21

The total vertical height of the melanoma, from the very top granular layer to the area of deepest penetration in to the skin, an instrument called an “occular micrometer” is used to measure the thickness of the excised tumor.

<1mm: 5 year survival is 95% to 100 %

1-2mm: 5 year survival is 80-96%

2.1-4mm: 5 year survival is 60-75%

4>mm: 5 year survival is 37-50%

Question 22

Melanoma: Prognosis

Answer 22

AJCC stage - 10 Year survival

I - 85%

II - 60%

III - 20%

Iv - <5%

Breslow thickness - 10 year survival rate

In Situ - almost 100%

1. 01-2mm - 89-95.3%
2. 01-4mm - 77.5-78.7%

>4mm - 5.1%

Question 23

Melanoma: Dx, Tx

Answer 23

Dx = Excisional biopsy (prefrred) - Palpate lymph glands

Work up: LDH can be prognostic - For Stage IIIA: CXR - IIIB/C Fine needle point aspitration of lymph involvement - Stage IV: consider abdominal or pelvic imaging/PET scan

Tx = Surgery: simple excision definative Tx for early stage melanoma. A wide local excision w/ sentinal lymph node biopsy and/or elective lymph node dissection (LND) is considered mainstay Tx for PTs w/ primary melanoma. In PTs w/ solitary or acvutely symptomatic brain Mts, surgical manahement may alleviate Sx and provide local control.

Tumor thickness recommened margins - In Situ =.5 Cm, less than 1 mm = 1 cm, 1-2mm = 1-2 cm, 2-4 mm = 2cm, >4 mm = at least 2 cm

Radiation:

Question 24

Measles (Rubeola)

Answer 24

Spread via respiratory droplets Incubation 9-12 days, clears 4-7 days.

Si/Sx = Prodrome of cough/coryza/conjunctivitis/fever then rash. Lesion fade chronologically - Lesions start as macular or mornilliform trash on anterior scalp and behind ears by day 2 or 3 down trunk to extremities - erythematous papules that coalesce spreading over face down the trunk to extremities, including palms/soles - Koplick spots: Pathognomonic white papules 1mm on buccal mucosa and pharynx.

Tx = Prevention: Vaccination with live virus at 15 Month and 5 Years - Supportive care

Question 25

Rubella (German Measles)

Answer 25

Toga Virus - Respiratory spread - Incubation 12-23 days

Si/Sx = Osten no Prodrome, but may have 1-5 days of fever/malaise/sore throat/Headache - Pain with lateral upward eye movement is characteristic - Lymphadenopathy (posterior cervical, suboccipital, and postauricular) - Lesions (pale/pink morbilliform macules, smaller than rubeola) - Begins on face, spreads inferior covering whole body in 24h - Resolves by day 3 - Forscheimer’s sign: Pitechiae on soft palate and uvula

Tx = Prevention (Vaccine with MMR) - supportive

Question 26

Fifth Disease (Erythema Infectiosum)

Answer 26

Benign/Infectious Exanthem (diffuse rash) caused by Parovirus - Respiratory droplet spread - later winter to early spring - No longer contagious when rash appears - Incubation 4-14 days.

Si/Sx = 3 Phase, no prodrome

1rst Phase - Abrubt/asymptomatic erythema of cheeks “Slapped Cheek“diffuse/macular

2nd Phase - By day 4 discrete erythematous macules and papules on proximal extremities and later, the trunk, evolving into lacy reticulate pattern on day 9

3rd Phase - Recurring stage, eruption is reduced/invisible, only reappearing with heat/bath/sunlight

Tx = Supportive

Question 27

Piyriasis Rosea

Answer 27

Acute self-limiting eruption common in the spring/fall with UNK cause (possibly viral)

SiSx = Herald Patch 2-5cm scaly lesion that may mimic tinea corporis

• Over 2 weeks oval or elleiptical erythematous patches with fine scale. Macular or Papular lesions develop on trunk/neck/extremities/skin folds (following them) in “Christmas tree” like pattern on trunk.
• May be pruritic
• May have prodrome of viral symptoms
• Lasts 3-8 weeks resolves spontaneously

Dx = Clin Presentation

Tx = Not Needed, reassure, Antihistamine for Itch.

Question 28

Morbilliform Reactions

Answer 28

Most common form of adverse drug eruptions

Pathogenesis = Type IV allergic reaction / T-helper cells

Commonly: Ampicillin, Amoxicillin, Bactrim

Si/Sx = Erythema with Macules/Papules initially on trunk, generalizing within 2 days - Can present within 2 weeks of exposure up to 10 days after stopping

Tx = Clears w/in 2 weeks of stopping - Symptomatic relief: Antihistamines, low potency Top Steroids

Question 29

Fixed Drug Reaction

Answer 29

Usually, meds taken intermittently NSAIDS/Sulfonamides/Barbituates

Pathophys = Mechanism UNK (Agen may function as Hapten and bind to Basal Keratinocytes causing inflammation)

Si/Sx = Round/Oval erythematous plaques, may be Pruritic/burning or asymptomatic. Reoccur at the same site w/ each exposure. Usually 6 or fewer lesions, Frequently 1 may appear anywhere 50% on genitals/oral mucosa.

Tx = Symptomatic: antihistamines or Topical steroids.

Question 30

Erythema Multiforme

Answer 30

Self limited eruption brought on by drug exposure/viral infections/or idiopathic (Sulfa, barbs, PCN, Phenytoin)

Si/Sx = Lesions begin as macules and become papular then vesicles and bullae form in the center of papules (multiple target like) - Localized to hands/feet, or may become generalized - Mucosal lesions are painful and erode - Fever/malaise

Tx = Avoid target substances, severe reaction may require systemic steroids

Question 31

Stevens-Johnson Syndrome & Toxic Erythema Necrolysis

Answer 31

Mucocutaneous blistering reaction from drug reaction - SJS thought to be severe variant of EM, and TEN to be a severe variant of SJS - Thought to be an immune response

Si/Sx = Fever mucosal inflammation - Lesions begin on trunk and may be painful. Ten exhibits higher fever and more epidermal separation then SJS

Tx = Withdrawal of offending agent - Tx at burn center for fluid and electrolyte imbalance/wound care. Corticosteroid

Question 32

Bullous Pemphigold **

Answer 32

Autoimmune d/o presents in 6th decade of life caused by autoantibodies, complement fixation/neutrophil/eosinophil. Leads to Bullous formation

IgG antibodies bind to basement membrane, activate complement system/inflammatory mediators - attracts inflammatory cells to basement membrane releasing proteases which cleave basal cells away from basal lamina causing blisters separating epidermis from dermis.

Si/Sx = Prodrome of urticarial lesions - Bullae are large and may contain serious or hemorrhagic fluid - Axillae/thighs/groin/abdomen

Course/Prognosis = Usually self-limiting over 5-6 years.

Diff = Blistering disease epidermolysis bullosa acquisita (EBA), Bullous Scabies erruption

Dx = Biopsy, immunofluroescence (C3 deposition is nearly always present in BP)

Question 33

Bullous Pemphigold: Treatment **

Answer 33

Localized or limited - Potent Topical corticosteroids - Clobetasol oint BID w/ occlusion

Moderate and severe - Same or Prednisone 0.5 to 0.75 mg/kg/day (taper cautiously as new lesions can appear)

Immunosuppressive meds can be considered for pts who cannot tolerate steroids.

• Azathioprine (Imuran) has been shown to have a steroid-sparing effect but has more side effects
• Mycophenolate mofetil (CellCept) 2 to 3 gr/day has been shown to be effective both as a monotherapy and in combo w/ corticosteroids
• Antibiotics can be beneficial for mild disease or as a steroid sparing agent
• Combo of tetracycline and niacinamide as effective as prednisone alone
• TCN 500mg QID w/ or w/out niacinamide 500 mg TID
• Doxy or minocycline 100 mg BID can be given in place of TCN
• Dapsone 50-300 mg/day can be used as steroid-sparing agent
• Start a dose of 50mg a day and increase by 25mg weekly until response
• Recalcitrant dz, IVIg and plasmapheresis can be used

Question 34

Pediculosis (Lice)

Answer 34

1-3 mm flat wingless insect with 3 pairs of legs - Female lays 300 nits (eggs) during lifetime on hair shafts (hatch in a week) - Head lice more common in warmer months - P.H. Capitis (Scalp), P.H. Corporis (body), Phthirus Pubis (Pubic/crabs)

Question 35

P.H. Capitus - Head Lice

Answer 35

Cannot survive for >3 days off the head - Dislodged by combs/towels/air - removing sweater, using hair dryer may eject adult lice more than 1 meter - Lice lay eggs on most fabric w/in 5 min of contact and > 50% hatch.

Most common in children, but happens in adults.

Si/Sx = Intense pruritus of the scalp w/ posterior cervical lymphadenopathy, excoriations, small specks of louse dung, on the scalp, Lice may be present w/ nits on the hair shaft

Question 36

P.H. Corporis - Body Lice

Answer 36

Does not need to live on the body - lives in clothing - Prefers cooler temps - lives and lays 10-15 eggs per day on the fibers of clothing close to the seams - Adult Female can survive as many as 10 days away from the body w/out a meal. (Associated w/ poor hygiene)

Si/Sx = Initially small pruritic papules progress to scratching/crusted/infected papules, Spares hands & Feet.

Question 37

P. Pubis - Crabs

Answer 37

Nicknamed Crab due to appearance, large claws allow lice to grasp coarser pubic hair groin/perianal/axillary areas- Heavy infestation can also involve eyelash/brow/facial hair/periphery of the scalp. - Less mobile resting while attached to human hair, cannot survive >1 day off human host.

Spread by close physical contact, commonly sexually.

Si/Sx = Intense pruritus, Small Blue Macules can present.

Question 38

Pediculosis: Diagnosis, Differential, Treatment

Answer 38

Dx = Hx/microscopic exam/biopsy

Diff = Scabies/Eczema/Delusions of parasitosis

Tx = Topicals OTC Nix Cream Rinse/RID Actin: Active ingredient Permethrin neurotoxin - Low concentration <1% - Kills Lice but not nits - Ovid Lotion: Most effective for head lice, kills lice/nits - not for children <6 months - Apply to dry hair, let sit 8-12 hrs, rinse/nit comb - Elimite cream (5% permetherin): Left on overnight, repeat in 1 week.

Bactrim: Destroys essential bacteria in louse’s gut

Vasaline: Asphyxiates lice/nits

Remember to Environmentally Eradicate - Wash at greater than 50-55 C for >5 mins - Seal in plastic bag for 2 weeks - Treat all family.

Question 39

Scabies

Answer 39

Sarcoptes scabiei - 8 legged mite (not visible with bare eye) - Burrow into epidermis and deposit feces/eggs - Irritant/allergens leading to type IV hypersensitivity ~30 days after infestation - PTs of all ages, but rarely infants <3 months - Consider w/ any PT having persistent pruritis not responding to topical steroids.

Si/Sx = Pruritic lesions vary considerably from vesicles/papules nodules located between web space of fingers/flexor aspect of wrist/axilla/antecubital/abdomen/umbilicus/genital/glutial area/feet - Spares the face, look for burrows a thin (approx width of human hair) short, gray brown wavy channel on the skin. - Hx of other family involvement.

Question 40

Crusted/Norwegian Scabies

Answer 40

Occurs in immunocompromised or debilitated PTs - Crusts and scales (teeming w/mites) Psoriasis like scaling around nails w/ crusting.

Question 41

Scabies/Norwegian Scabies: Differential, Diagnosis, Treatment

Answer 41

Differential = Bite Reaction/Atopic Derm/Delusions of parasitosis

Dx = Hx/scraping/biopsy - Treatment on presumption of scabies sometimes necessary

Tx = Topical meds: Permethrin 5% cream (Elimite) apply to all areas of skin below the neck for 8-12 hrs. Repeat in 1 week) - Lindane 1% lotion or cream (Kwell) more toxic (no pregnancy/kids <2) - Percipitated Sulfer Ointment 6% best for pregnant PTs breastfeeding, applied to all areas from the neck down, wash off 8-10h later.

Oral meds: Ivermectin (Stromectol) Causes paralysis in invertebrates, 200 ug/kg/day x2 days

After Tx: Wash everything in hot water or removed for 72h, treat family.

Question 42

Brown Recluse Spider (Loxoscelism)

Answer 42

Causes necrotic Arachnidism (in US) - Commonly in the Midwest/Southwest - In woodpiles/grass/rocky bluffs/barns - Stings in defense - Look for Dark, violin-shaped markings, 3 sets of eyes, light brown - Venom contains Phospholipase enzyme Sphingomyelinase D (major Toxin)

Si/Sx = Localized: Bite becomes painful after 3 Hrs, Extensive necrosis develops w/ edema within 8 Hrs with Bulla and surrounding Erythema/Ischemia that can extend to muscle - In 1-week central portion becomes gangrenous/dark

Tx - Rest/Ice/Elevation, Analgesics, Tetanus Proph, Surgical Debridement

Question 43

Black Widow Spider (Latrodectism)

Answer 43

Continental US/Caribbean - Found in Wood piles/outhouse seats - Red Hourglass - Bites when disturbed.

Si/Sx = Locally limited small circle of redness w/ central reddened fang puncture site surrounded by area of blanching and outer halo of red (target appearance) - Systemically pain/cramping w/in an hour, spreads to extremities and trunk - Tachycardia/HTN - Fevers/Chills/vomiting/violent cramps/Delerium/partial paralysis - Abdominal pain most severe

Tx - ACLS - Antivenom admin at ER (risk of allergic reaction) - Analgesics (morphine) - Antihistamine - Tetanus