Derm Flashcards
Describe 10 questions of the dermatologic history
- Onset (primary lesion, timing)
- Pattern of spread
- Symptoms
- Treatments
- Medications & allergies
- PMH of skin, other
- FH for skin conditions
- Work/hobby contactants (including pets)
- Recent travel/exposures
- Sexual history
Describe the 5 components of the dermatologic physical exam
- Type of lesion; primary/secondary/special
- Distribution
- Configuration
- Color
- Epidermal (surface change) or dermal (no surface change)
What is the Koebner phenomenon?
Refers to skin lesions appearing on lines of trauma, e.g. psoriasis appearing at biopsy site or area of sunburn
What is the Auspitz sign?
the appearance of punctate (pinpoint) bleeding spots when psoriasis scales are scraped off
What is the id reaction?
In an id reaction, ERYTHEMATOUS VESICLES usually are seen on the lateral aspects of the fingers and the palms and are typically PRURITIC. This eruption of vesicles is usually sudden and classically occurs in response to an intense inflammatory process, especially FUNGAL infections (e.g. tinea pedis), taking place SOMEWHERE ELSE on the body. Treatment of the underlying infection results in resolution.
What is the Nikolsky sign?
A clinical dermatological sign, when slight rubbing of the skin results in exfoliation of the outermost layer, forming a blister within minutes.
Nikolsky’s sign is almost always present in toxic epidermal necrolysis (TEN) and is associated with pemphigus vulgaris. It is useful in differentiating between pemphigus vulgaris (where it is present) and bullous pemphigoid (where it is absent).
Describe the system for classifying skin phototypes.
I - white, very fair, red or blond, blue eyes, freckles
always burns, never tans
II - white, fair, red or blond, blue, hazel, or green eyes
usually burns, tans with difficulty
III - cream white, fair with any eye or hair color, very common
sometimes mild burn, gradually tan
IV - brown, typical Mediterranean caucasian skin
rarely burns, tans with ease
V - dark brown, mideastern skin types
very rarely burns, tans very easily
VI - black
never burns, tans very easily
Name and describe the three stages of hair growth.
Anagen - growth; 85% of hair, rapidly dividing
average 3 years
beard, scalp - long anagen
eyebrows, pubic - short anagen
Catagen - regression; apoptosis-driven, 3% of hair
3 weeks
Telogen - resting; 10-15% of hairs
about 3 months
extremities, eyebrow, pubic/axillary - long telogen
Differences between MSSA and MRSA cellulitis
Drugs to treat each
MRSA is a more effective colonizer; has higher rates of adverse outcomes and treatment failure; has higher cost of care
MRSA: Clindamycin, TMP-SMZ, Vancomycin
MSSA: Cephalexin, dicloxacillin
Name the organism(s) associated with impetigo
S. aureus, GAS
Name the organism(s) associated with erysipelas
GAS
Name the organism(s) associated with cellulitis
S. aureus, GAS
Name the organism(s) associated with erythrasma
Corynebacterium minutissimum
Name the organism(s) associated with necrotizing fasciitis
GAS, S. aureus, Clostridium, polybacterial
Name the organism(s) associated with pitted keratolysis
Kytococcus sedentarius
Name the organism(s) associated with tinea capitis, barbae, corporis, unguium, cruris, pedis
tinea pedis: Trichophyton rubrum
tinea capitis: Trichophyton tonsurans
tinea corporis: T. rubrum; M. canis
tinea cruris: T. rubrum; T. mentagrophytes
tinea barbae: T. verrucosum; T. mentagrophytes
tinea unguium: T. rubrum; T. mentagrophytes
Name the organism(s) associated with tinea versicolor
Malassezia (tinea versicolor is not a true tinea….more accurate name is pityriasis versicolor)
Name the organism(s) associated with candidiasis
yeast, C. albicans
Name the organism(s) associated with molluscum contagiosum
poxvirus
Name the organism(s) associated with verrucae
HPV
KOH - method and findings
scraping + slide + drop of KOH + microscope
looking for fungal hyphae; “spaghetti & meatballs”
diascopy - purpose and technique
to check for blanching: clear slide + press against lesion and observe through slide
viral culture - key points
- Take a sample by rubbing a sterile swab on the lesion
· Must include cells not just fluid from the blister
· Optimal if removed during the acute (worse) phase
· highly dependent on appropriate selection, collection, and handling of biological specimens.
· When delays are expected, viral samples should be refrigerated at 4⁰C
fungal culture - key points
May be done after a KOH prep
Results may take weeks
Limited application
Samples easily contaminated by bacteria
acetowhitening
- -purpose
- -indications
- -collection procedure
- -clinical use
Purpose: to identify areas of squamous cell change
Indications: abnormal Pap or HPV test; abnormal cervix appearance; abnormal bleeding
Collection procedure: during colposcopy, apply acetic acid solution to cervical area of concern; biopsy areas of whitened cells (abnormal) and study histologically
Clinical use: diagnose cervical dysplasia, HPV
Gram stain
- -purpose
- -procedure
- -interpretation
Purpose: to differentiate between Gram-negative and Gram-positive bacteria; to visualize morphological bacterial features
Procedure:
- specimen on slide
- apply crystal violet, rinse
- apply iodine, rinse
- apply decolorant, rinse
- apply counterstain (safranin red), rinse
Interpretation: Gram-positive = dark purple or blue, Gram-negative = pink/red
Wood's light What are the clinical interpretations of interest? Erythrasma Pseudomonas Tinea capitis Tinea versicolor Pigmented lesions of the epidermis Pigmented lesions of the dermis Vitiligo False positives
Erythrasma: coral pink
Pseudomonas: green
Tinea capitis: T. tonsurans does not fluoresce; Microsporum fluoresces bright green
Tinea versicolor: orange-yellow
Pigmented lesions of the epidermis: accentuated
Pigmented lesions of the dermis: faded
Vitiligo: white
False positives: scale, soap, fibers, ointments, scars
bacterial (wound) culture
Specimen must contain:
What are the indicative factors about the growth conditions in the lab?
Specimen must contain exudate and/or necrotic tissue!
Much can be learned from the medium on which growth takes place/doesn’t occur, as well as the oxygen availability
herpes serology
Purpose
Indications
Purpose: Designed to detect an antibody response in serum samples after an exposure; To distinguish between two serotypes; HSV 1 (oral) and HSV 2 (genital); to enable targeted treatment with appropriate antivirals
Indications: PE findings e.g. vesicles, pustules, shallow ulcers with erythematous base; recent exposure; pregnant women
Tzanck smear
Purpose
Technique
Findings
A Tzanck smear is a cytologic technique most often used in the diagnosis of herpesvirus infections (HSV or VZV). An early vesicle, not a pustule or crusted lesion, is unroofed, and the base of the lesion is scraped gently with a scalpel blade. The material is placed on a glass slide, air-dried, and stained with Giemsa or Wright’s stain. MULTINUCLEATED EPITHELIAL GIANT CELLS suggest the presence of HSV or VZV; culture or immunofluorescence, or genetic testing must be performed to identify the specific virus.
melanoma main risk factors? what is the number one indicator of prognosis? what is the ugly duckling sign? what are 3 factors of assessment? What is the ABCDE assessment?
Main risk factors: UVR; > 100 nevi; skin phototype I or II
The number one indicator of prognosis is thickness of lesion/tumor. Thicker is bad.
Ugly duckling sign: one mole stands out as different-looking amongst a field of moles
3 assessments: dermoscopy by an experienced clinician; excision with NARROW margins (to preserve tissue for later excisional surgery); histological assessment by an experienced dermatopathologist
ABCDE: Asymmetry Border Color Diameter Elevation/Evolving
Mohs micrographic surgery
- What are the benefits?
- What kind of cancer is it the most effective in curing?
- What other cancers is it used for?
- High cure rate with lowest cosmetic issues
- Highest cure rates for BCC; slightly less with SCC
- May be used for some melanoma as well
What is the difference between eczema and dermatitis?
The terms eczema and dermatitis are used interchangeably, denoting a polymorphic inflammatory reaction pattern involving the epidermis and dermis. There are many etiologies and a wide range of clinical findings. Acute eczema/dermatitis is characterized by pruritus, erythema, and vesiculation; chronic eczema/dermatitis, by pruritus, xerosis, lichenification, hyperkeratosis, ± fissuring.
Name 6 general treatments for psoriasis.
- emollients/keratolytics
- corticosteroids
- coal tar
- phototherapy
- methotrexate
- cyclosporine
Name 5 adverse side effects of topical steroids.
- HPA suppression
- dermatitis
- hypopigmentation
- skin atrophy
- striae
Describe asteatotic dermatitis
A common pruritic dermatitis that occurs especially in OLDER persons, in the winter in temperate climates—related to the low humidity of heated houses.
—The sites of predilection are the legs, arms, and hands but also the trunk.
—Dry, “cracked,” superficially fissured skin with slight scaling.
—The incessant pruritus can lead to LICHENIFICATION, which can even persist when the environmental conditions have been corrected.
—The disorder results from too frequent bathing in hot soapy baths or showers and/or in older persons living in rooms with a high environmental temperature and low relative humidity.
What condition is described as “dew drops on a rose petal” presentation?
Herpes simplex (grouped vesicles on an erythematous base)
What do you think if you hear “rodent ulceration”?
Basal cell carcinoma
What do you think if you hear “umbilicated”?
molluscum contagiosum
What is a classic diagnostic sign for warts?
black dots (thrombosed capillaries)
What is a side effect risk of cryotherapy (e.g. liquid nitrogen)?
hypopigmentation, hyperpigmentation
What are three treatments for warts?
freezing, salicylic acid, duct tape
If you see comedones you know it’s _____
acne
What are the TOPICAL treatments for acne?
benzoyl peroxide
retinoids
topical ABX
keratolytics/salicylic acid
What are the SYSTEMIC treatments for acne?
oral antibiotics (doxycycline, minocycline)
isotretinoin
intralesional steroids
OCPs
Differences between acne vulgaris and rosacea:
distribution
comedones
acne vulgaris: face/trunk
rosacea: cheeks/chin, forehead/nose
comedones: MUST have for acne vulgaris; do NOT have in rosacea
How much mass is a fingertip unit?
1 FTU = 0.5 g
Which is least drying? Which is most drying? powder cream lotion tincture gel ointment
LEAST DRYING (best for conditions like eczema): OINTMENT
CREAM is the next most emollient/least drying
LOTION
GELs can be drying (depends on alcohol content)
TINCTURES are drying (the purpose of a tincture is to dry)
POWDER
Define ointment cream lotion gel tincture powder
ointment: homogeneous, greasy, semi-solid; no surfactant or detergent. E.g. Vaseline, triamcinolone
cream/lotion: These are emulsions with oils and water and include a surfactant so the two will mix together. They can contain preservatives, humectants and stabilizers as well (which can be irritants). They need to be rubbed in, and therefore can be drying. Cream is a more solid form, while a lotion is a more liquid form. The more liquid it is, the more drying it will be.
gel: Non-greasy mixtures of propylene glycol and water (can contain alcohol). They have a translucent appearance and are sticky.
Gels with alcohol are best for acute exudative lesions (poison ivy dermatitis)
Alcohol-free gels should be used for dry and scaling conditions.
tincture: plant or animal extract in alcohol
powder: powdered drug, or drug mixed with a delivery powder such as corn starch. Good for intertriginous areas to dry them (e.g. axilla, inguinal)
What is the MOA of topical corticosteroids? How is potency determined?
MOA: anti-inflammatory, inhibit cell division, cause vasoconstriction
Potency is determined by ability to vasoconstrict
What is the lowest potency topical corticosteroid?
What are the intermediate potency topical corticosteroids? (4)
What are the highest potency topical corticosteroids? (3)
What classes are the highest potency and the lowest potency?
lowest: hydrocortisone
intermediate: triamcinolone, fluocinolone, halcinonide, mometasone
highest: betamethasone, clobetasol, halobetasol
Class I is the highest potency; class VII is the lowest potency.
What is tachyphylaxis?
Defined as the decrease in drug response when used over a prolonged period of time, tachyphylaxis is commonly observed during corticosteroid topical therapy. It is now thought that decreased adherence may be a contributing factor, rather than loss of corticosteroid receptor function. Increase in adherence may be achieved by asking patients to use it only on weekends (weekend therapy) or specific days of the week (pulse therapy).