Dermatology Flashcards
How are skin lesions described?
“MAD”
Morphology: shape, color, elevation, margination, etc.
Arrangement: single, grouped, arciform, annular, etc.
Distribution: localized, disseminated
diascopy
glass slide or diascope pressed on skin; blanching indicates intact capillaries
purpura does NOT blanch
KOH prep
mount skin scraping on KOH to dissolve keratin and cellular material; fungi not affected
identifies fungal or dermatophyte infection
Wood’s light exam
exam skin under UV light
telangiectasia
dilated, small, superficial blood vessels
Lichenification
thickened skin with distinct borders, often from excessive scratching or prolonged irritation
macerated
swollen and softened by increase in water content; appearance that skin gets when left in water too long
verrucous
irregular, rough, and convoluted surfaces
circumscribed, elevated lesion containing serous fluid or blood less than 5 mm and greater than 5 mm
vesicle
bulla
solid, palpable lesion less than 5 mm and greater than 5 mm
papule
nodule
flat, non-palpable lesion less than 1 cm and greater than 1 cm
macule
patch
petechiae
minute hemorrhagic spots that do NOT blanch by diascopy
types of contact dermatitis
irritant (chemicals) diaper rash (prolonged urine/feces contact) allergic (type IV cell mediated hypersensitivity reaction)
acute itching and burning rash with well-demarcated areas of erythema
contact dermatitis
How is contact dermatitis confirmed in lab?
Patch test
contact dermatitis treatment
Avoid offending agent
Wet dressings with Burrow’s solution
Topical steroids
Supportive: clean with mild soaps, antihistamines for itch (Calamine lotion)
Auspitz sign
bleeding after scale removed
ex: psoriasis
Patch test
shows hypersensitivity reaction in skin allergies
ex: contact dermatitis
Darier sign
urticarial flare produced by rubbing skin
Nikolsky sign
rubbing skin causes blister
Atopic dermatitis also referred to as _______.
eczema
Atopic dermatitis symptoms
- Dry itchy skin often involving FLEXURAL surfaces (back of knees, wrists, anterior elbow), face, dorsum of hands and feet
- Lichenified skin
- Secondary infections like staph
Atopic dermatitis treatment
Avoid dry air, limit bathing and soap use
Hydration and topical emollients
Antihistamines
Topical steroid
Presentation of contact dermatitis
Vesicles
Crusted lesions
Pruritus
The location and distribution are keys to dx
- Linear vesicles on the forearms or lower legs are often poison ivy
How is impetigo ruled out as cause of rash?
Gram stain
eczema is in close association with what other conditions?
ATOPY: eczema, asthma, allergic rhinitis
signs/sx’s of seborrheic dermatitis
- Flakey, dry, itchy skin
- Found in oily places such as body folds, face, scalp, genitalia
seborrheic dermatitis in adults commonly known as ______ and in infants its called _______.
dandruff
cradle cap
seborrheic dermatitis treatment
- OTC dandruff shampoo (selenium sulfide)
- UV radiation
- Ketoconazole shampoo
- Topical steroids for severe cases
cradle cap: olive oil compresses, baby shampoo
A skin disorder characterized by repetitive itching and scratching. This may be secondary to eczema, psoriasis, bug bites, psych disorders, etc.
Lichen simplex chronicus
Describe rash of Lichen simplex chronicus
- Lichenified skin with well defined borders
- Plaques
- Darkened skin
- Scratch marks
Lichen simplex chronicus treatment
- Must reduce scratching
- Lotions and creams to keep skin moist
- Antihistamine
- Cortisone cream
Patients with dyshidrosis often have a history of _____.
atopy
sign of dyshidrosis
small clear vesicles in clusters (“tapioca” appearance) and occasionally bullae
usually on hands and feet
painful fissures if vesicles rupture, scaling, Lichenification
dyshidrosis treatment
- Reduce stress in life
- Avoid skin irritation by using gloves and cream to keep skin from drying out
- Topical steroids
- Wet dressing with Burrow’s solution
Some medications that commonly have derm side effects
Penicillin - rash
Percocet - itch
Itchy, shiny lesions which are solid and raised with white lines (Wickham striae).
Lichen Planus
The 4 P’s of Lichen Planus
Pruritic
Purple
Polygonal
Papules
Lichen Planus treatment
- Strong topical steroid
- Cyclosporine mouthwash if oral lesions
- Systemic therapy may be necessary
- Phototherapy
Hallmarks of pityriasis rosea
Herald patch - solitary pink plaque with raised borders, commonly on abdomen 1-2 weeks before rash breaks out
Salmon-colored papular rash eruption on trunk in Christmas tree pattern
pityriasis rosea treatment
- Self limiting, typically 3-8 weeks
- May use lotion or antihistamines
Chronic autoimmune skin disorder characterized by red flaky, scaling skin that is dry and itchy
Psoriasis
Describe rash of psoriasis
- salmon colored, well defined raised papules and plaques, dry/itchy with SILVER SCALES
- most often scalp and EXTENSOR surfaces of elbows and knees
- scratching causes more lesions (Koebner phenomenon), Auspitz sign
Associated symptoms of psoriasis besides rash
Onycholysis (separation of nail plate)
Arthritis in hands and feet
Psoriasis treatment
Keep skin moist Topical steroid or topical Vit D Systemic steroid may be necessary if widespread Tazarotene gel (topical retinoid) Severe: PUVA, Methotrexate
3 variations of psoriasis
vulgaris - 80%
erythroderma - lesions all over body
guttate - disseminated pattern, often after strep throat
pustular - widespread pustules; life-threatening
What can occur if psoriasis tx suddenly stopped?
psoriatic erythroderma; can be fatal due to systemic inflammation and difficulty regulating body temp
Most common infection that predisposes patient to Erythema Multiforme
Herpes infection
Which medications most commonly cause SJS and TEN?
Sulfonamides, penicillin, phenytoin…..
Hallmark rash of erythema multiforme
target lesion- pink red ring with pale center
erythema multiforme treatment
Acyclovir if related to herpes flare up, otherwise self-limiting (2-6 wks)
Systemic steroids if severe
PE findings of SJS and TEN
High fever
Necrotic epidermis, loss of skin in sheets
Nikolsky sign
SJS and TEN treatment
- d/c causative agent and send to burn unit
- fluid and electrolyte management very important
Initially a urticarial rash (hives) that turns into tense, large bullae typically in axillae, groin, and thighs
bullous pemphigoid
Starts as painful lesions in mouth and then clear fluid-filled vesicles or bulla break out on skin. Lesions are flaccid and easily ruptured with (+) Nikolsky sign
Pemphigus vulgaris
Pathophysiology of pemphigus vulgaris
autoimmune IgG mediated loss of cell-to-cell adhesion
Gold standard of diagnosing rashes
skin biopsy
Generic treatment for most rash outbreaks
topical steroids for minor outbreak systemic oral steroids for more severe abx for secondary infection fluid and electrolyte management antihistamine for itch
Name for typical adolescent acne
acne vulgaris
How is mild acne treated?
hygiene, diet, etc.
topical retinoids
topical salicylic acid
How is acne treated if inflammatory lesions present?
topical benzoyl peroxide, erythromycin, clindamycin, or sodium sulfacetamide
How is severe or cystic acne treated?
- Add abx like tetracycline, erythromycin, or clindamycin
- refer to dermatologist for Accutane (isotretinoin)
I came in to see my physician assistant because of…
Face appears flushed
Small papulopustules
Facial telangiectasia
Rhinophyma (enlarged nose) may be seen
Acne Rosacea
Acne Rosacea treatment
- Remove aggravators (sun, emotional stress, spicy food, heavy exercise, alcohol)
- Metronidazole most effective
- topical abx or oral abx if very severe
What to warn patient about Accutane?
side effects: dry eyes and mouth, mood swings, joint pain, visual changes, leukopenia
TERATOGENIC - patient put on birth control
If ________ left untreated 20% will go on to squamous cell carcinoma.
actinic keratosis
Describe actinic keratosis lesion
2-10 mm macules or papules
pink or hyper pigmented
feel like sandpaper
Actinic keratosis treatment
Typically liquid nitrogen
5% 5-FU cream
lesion with “stuck on appearance”
seborrheic keratosis
seborrheic keratosis treatment
they are benign so usually do nothing
Lice treatment
Permethrin 1% cream
presentation of scabies
severe itching
burrowing of skin
commonly web spaces of hands
Scabies treatment
Permethrin 5% cream; applied once to whole body overnight and rinse in the morning, all family and sexual partners should be treated
Where are brown recluse spiders located? how are bites treated?
only mid southeastern states
tx: wash it, keep it clean, +/- abx
Symptoms of black widow bite? how are bites treated?
sx: pain, muscle cramping, tachycardia; may have N/V
tx: antivenom
shiny, pearly nodule
basal cell carcinoma
basal cell carcinoma treatment
Mohs surgery
+/- radiation in elderly
systemic disease caused by herpes virus 8
Kaposi Sarcoma
Kaposi Sarcoma typically very slow developing, but in conjunction with ______ it progresses quickly.
AIDS
I came in to see my physician assistant because of…
Red or purple plaques on the skin and mucosal surfaces GI lesions Difficulty swallowing Pulmonary lesions Difficulty breathing Cough Chest pain
Kaposi Sarcoma
Lesion that is most common cause of cancer
basal cell carcinoma
Kaposi Sarcoma treatment
No cure
Treat AIDS with anti-retroviral therapy
Radiation
Cryotherapy
Characteristics of mole that make it a melanoma
A = asymmetry B = irregular borders C = color changes D = diameter +6mm E = evolving over time F = firm G = growing
How can melanoma be dx’d?
biopsy
dermoscopy
CT/PET scan
Melanoma treatment
Prevention is key! - sun protection, no tanning beds
Surgical excision
Sentinel lymph node biopsy
Radiation/Chemo
How to predict survival rates of melanoma?
tumor thickness
I came in to see my physician assistant because of…
A growing nonhealing rough, bumpy, scaly patch
Lesions have a variable appearance
90% are found on the head and neck
squamous cell carcinoma
squamous cell carcinoma treatment
Mohs surgery
Chemo/Radiation
Most common kind of alopecia
androgenetic baldness
Causes of scarring alopecia
trauma, infections, radiation, scleroderma, etc.
Androgenetic baldness tx
Minoxidil 5% solution applied BID
Treat underlying cause
onychomycosis
fungal infection of toenail
typically painless
thickened, brittle; white, yellow, or green
How is fungal nail dx’d?
KOH prep, culture
Treatment of onychomycosis
- systemic antifungal (Terbinafine first line)
- topical antifungal (Ciclopirox)
- good hygiene
common cause of paronychia
staph aureus infection of skin around nailbed
Paronychia treatment
- warm soaks
- abx (Cephalexin, Dicloxacillin) then an I&D if abscess
- hydrocortisone cream prn
Warts found typically in the gential/anal area. Sexually transmitted by the human papillomavirus (HPV) types 6 and 11
Condyloma acuminatum
Condyloma acuminatum tx
No true cure
- Prevention: safe sex, Gardasil protects against some HPV types
- Laser removal
- Cryosurgery
HPV types 16 and 18 are linked to _______.
cervical cancer
Vesicles location: HSV type 1 are usually _____ and type 2 are ______.
oral (cold sore)
genital
Herpes Simplex tx
No true cure
- Typically self limiting
- Topical antiviral (5% acyclovir)
- Oral antiviral (acyclovir, valacyclovir)
- Tylenol and ibuprofen
Describe wart of molluscum contagiosum
Flesh colored Dome shaped Pearly or waxy Umbilicated Not painful or pruritic
How is molluscum contagiosum transmitted?
wet skin to skin contact -> “water warts”
sexual activity
What virus leads to chicken pox?
varicella zoster
Hallmarks of chicken pox rash
- Dew drops on a rose petal
- Lesions appear in crops: you get a certain number of lesions on day 1 and then more appear on day 2 and so on
How is chicken pox positively dx’d in lab?
Fluid taken from the vesicles and prepared with a Tzanck smear will show multinucleated giant cells
chicken pox treatment
- Supportive care
- Do not give aspirin to kids under 19
- Prevent or treat secondary infections
- Antiviral may be appropriate in the immunocompromised
- A live attenuated virus is used for vaccination. It is always given twice
I came in to see my physician assistant today because of…
Severe burning pain and hypersensitivity before vesicular lesions are visible
Typically affect one dermatome
Shingles (Zoster)
Shingles treatment
Acyclovir x 7 days
Define exanthem
widespread rash
Koplik spots are pathognomonic for ______.
measles
clusters of white spots on buccal mucosa. fade as rash begins to appear
Characteristics of measles rash
- Red blanching maculopapular rash
- Appears 3-5 days after first signs of illness
- Starts behind ears, moves to face/neck, then travels down (imagine bucket of red paint poured over head)
- Pruritic
- Lesions darken to brown and fade in order they appeared
Measles treatment
Supportive care
Self limiting disease only progressing with secondary infection
Live attenuated vaccine is given at 12 months old and a booster is given before a child enters school
- Symptoms of strep throat
- Rash: like painful sunburn with tiny bumps that blanch with pressure.
Feels like “sandpaper” - Bright red swollen strawberry tongue
Scarlet Fever
Scarlet Fever tx
abx x 10 days
How does Rubella present?
- Flu like symptoms for about a week
- Rash on the face which spreads to the trunk and out to the extremities; typically fades after about three days
Rubella tx
Live attenuated virus for vaccination
Supportive treatment
Rash of erythema infectiosum (Fifth Disease)
SLAPPED CHEEK
Red macular rash on cheeks with circumpolar pallor
Lacy red rash on trunks, arms, upper legs
Erythema Infantum (Roseola) signs/sx
- High fever up to 105 for several days then drops, rash appears
- Pink maculopapular rash
- Lasts a few hours up to 3 days
Erythema Infantum (Roseola) tx
- Supportive care
- Monitor fever closely (number one cause of febrile seizures)
Cellulits most commonly caused by ________ and _______ infections.
staphylococcus and streptococcus
Describe skin of cellulitis
warm, red, swollen
lymphadenopathy
fever/chills
Cellulitis treatment
Oral penicillinase resistant penicillin – dicloxacillin or a cephalosporin
If admitted IV cephalosporins
Draw out the margins to follow the treatment
How is erysipelas different than cellulitis?
more superficial
How is impetigo caused?
skin to skin contact
very poor hygiene
Signs of impetigo
Lesions: thick crusted, honey colored scabs
Define dermatophyte infection
ringworm fungal infection affecting skin, hair, and/or nails
Examples of dermatophyte infections
tinea pedis - foot (athletes foot) tinea cruris - groin (jock itch) tinea corporis - trunk, legs, arms, neck tinea barbae - beard area tinea unguium - nails tinea capitus - head
Signs of ringworm
- Red raised ring with a central clearing and distinct borders
- Itching, stinging and burning
Labs helpful to dx ringworm
KOH prep to confirm fungus
Woods light or culture may be useful
Dermatophyte tx
- Topical creams, ointments, lotions, sprays, and powders
- Keep area clean and dry
No steroids!!!
Chronic fungal infection with tan or pink macules that don’t tan; sx’s worse in hot or humid climates
tinea versicolor
KOH of tinea versicolor reveals what?
yeasts in spaghetti and meatball appearance (round yeasts with filaments)
tinea versicolor treatment
Topical:
Selenium Sulfide lotion 2.5% x 7 days; Ketoconazole shampoo used weekly
Systemic:
Ketoconazole 200 mg daily x 7 days (delivered through sweat to skin. Do not shower for 8 hours after taking)
Fluconazole 300 mg two doses 14 days apart
epidemiology of Acanthosis Nigricans
African Americans younger than 40 yo
causes of acanthoses nigricans
- May be inherited
- May be due to underlying endocrine disorders: DM 2, PCOS, Hypo or hyperthyroidism, Cushing’s disease, Acromegaly
Pregnant female comes in with skin discoloration upon sun exposure. The lesions are tan or brown and have clear borders. Likely dx?
melasma
Causes of melasma
pregnancy or oral contraceptive
Patient comes in for brown or black poorly defined area of thickened or velvety skin in skin folds
Acanthosis Nigricans
I came in to see my physician assistant because of…
Depigmentation of the skin
Usually begins in the extremities
Well defined Irregular borders
vitiligo
Vitiligo treatment
UV light therapy
PUVA – UV light with psoralen which makes the skin more susceptible to the light
Melanocyte transplant
Differentiate first, second, and third degree burns
First degree – NO blisters (Don’t consider when assessing Total surface area of the burn since doesn’t affect outcome or factor into electrolyte management)
Second degree – blistering
Third degree – no hair or sweat glands
Rule of nines for estimating surface area
Palm is 1% Head and neck 9% Each arm is 9% Each leg is 18% Anterior trunk 18% Posterior trunk 18% Genitalia 1%
How are burns treated?
First degree burns: cool compresses
Second and third degree burns:
- Don’t pop blisters!
- Tetanus shot
- Silver sulfadiazine to protect wounds from infection
- Fluids and Electrolytes
- Surgical debridement of wounds often necessary
Parkland formula for fluids in first 24 hrs of second and third degree burns
Total SA burned (%) x Wt (kg) x 4ml
Give half in first 8 hrs and second half over next 16 hrs
Example: 180 lb man with both arms completely burned
81 kg x 18 x 4 = 5832 ml = 5.9 liters lets round to 6 liters
Give 3 liters of Ringers lactate in the first 8 hours and 3 liters over the next 16 hours
- Use rule of 9 to estimate SA *
I came in to see my physician assistant today because of…
Chronic cysts which vary in size from the size of pea the size of a baseball. They are extremely painful and inflamed. Located on underarms, inner thighs, groin and buttocks.
Hidradenitis Suppurativa
Hidradenitis Suppurativa tx
- Reduce predisposing factors: Weight loss, stop OCPs, wear loose fitting clothing
- Abx
- Incision and drainage prn
- Steroid injection
A benign tumor of fat cells. They are soft, mobile and usually non tender.
lipoma
This can be a cyst, an abscess, a sinus or a fistula near the natal cleft of the buttocks.
Pilonidal Disease
Wheal and flare reaction to animal dander, insect bites, pollen, shellfish, nuts, stress, etc.
Urticaria (Hives)
Perioral dermatitis treatment
AVOID topical steroids (typically the cause)
Use metronidazole, erythromycin, or oral minocycline or doxycycline
Chronic venous insufficiency due to valvular incompetency leading to dermatitis, edema, hyper pigmentation, fibrosis, and ulceration
stasis dermatitis
Lab studies for chronic venous insufficiency
Doppler U/S
Well-circumscribed plaques that are highly pruritis, setting up a cycle of itch-scratch lesions
Lichen simplex chronicus
Pathophysiology of psoriasis
greatly increased epidermal cell turnover; 28x normal
Treatment of bullous pemphigoid and pemphigoid vulgaris
Systemic prednisone
Immunosuppressants
Azathioprine
How can acne vulgaris and acne rosacea be distinguished?
acne rosacea has no comedones
Bacteria in hot tubs that causes folliculitis
Pseudomonas
Oral griseofulvin can treat what derm disorder
tinea capitus
tan-pink well demarcated WAXY plaque with raised borders; often associated with diabetes
necrobiosis lipoidica
Rash caused by zinc deficiency?
scaling red rash
Signs of aplasia cutis congenita?
asymptomatic ulcerations of scalp
Dome-shaped nodule with “dimple sign”
dermatofibroma
What are solar lentigines?
asx brown macules from sun; no malignancy risk
Sign of dermatomyositis?
periocular erythema and edema
proximal muscle weakness
widespread vesicles with gingival involvement, fever, and adenopathy likely from what bug?
HSV
xanthomas commonly caused by what?
hyperlipidemia
DDX of target lesion
Lyme disease
Erythema multiforme caused by HSV