Intro to Dermatology Flashcards
What is the correct order of history and physical in dermatology?
Physical first, then history
Elements of a derm history
- Onset
- Pattern of spread
- Sx
- Tx
- Contacts
- Meds
- Family Hx
- Work and hobby contactants
- Travel/exposures
- Sexual Hx
Steps to physical exam
- type/morphology of lesion
- color, consistency, texture, surface changes
- individual lesion configuration
- distribution
Things to examine together:
- Scalp, hair, nails and teeth
- Hands and feet
What differentiates dermal vs epidermal lesions?
Epidermal: - Sharply defined border - Surface change - Scaling Dermal: - Smooth appearance
What does “Koebner phenomenon” refer to?
Appearance of lesions along an area of trauma
Papulosquamous = ?
- Distinct papules or plaques
- Scaling
- Primarily epidermal features
Eczematous = ?
- Irregular plaques
- Oozing and crusting
- Lots of dermal activity
What is “honey colored crust” suggestive of?
Impetigo
Auspitz sign
Pinpoint bleeding when scales are removed from psoriatic plaques/warts
Gottron sign
Pink or violaceous macular or papular erythema of hand, knee, elbow or ankle joints with dermatomyositis
Hair collar
Ring of hair around a congenital lesion such as a meningocele
Nikolsky sign
Lateral pressure results in sloughing of skin in blistering disorders (e.g., SJS)
Oil drop sign
Distal yellowing of nail beds due to psoriatic disease
Ugly duckling sign
Pigmented lesion that stands out from surrounding lesion, indicative of melanoma
What do you look for in a Tzanck smear that’s indicative of herpes?
Giant multi-nucleated cells
Impetigo vs. cellulitis
Epidermal vs. Dermal
Bullous impetigo
Localized staph scalded skin reaction
Most common cause of bullous impetigo
S. aureus phage group II
What causes cleavage of desmoglein in bullous impetigo?
Exfoliative Toxin- A
Important clinical signs of necrotizing fasciitis
- Gas in tissue
- Cutaneous anesthesia
- Bullae
- Ecchymosis that may precede necrosis
What are the hallmarks of a tinea infection?
- Round
- Accentuated border
- Scale
What does “spaghetti and meatballs” suggest
Tinea versicolor infection
What does grouped vesicles on an erythematous base indicate?
Herpes simplex
What should you look for in the absence of vesicles with herpes infections?
Stellate, cribriform appearance
What is Hutchinson’s sign?
Zoster involvement on the tip of the nose. Usually indicates that the eye is involved as well.
Difference in presentation: smallpox vs. chicken pox
- Smallpox vesicles all appear at the same time and progress together
- Chicken pox lesions appear at different times, so some will be new and some will be advanced
“Hot tub folliculitis” bug
Pseudomonas
Majocchi’s granuloma treatment
Oral terbinafine 250 mg QD for 6 - 12 weeks
The default assumption with any SSTI should be that it is?
Staph or strep.
What often happens with OTC topical antibiotics?
- resistance (s. aureus w/in 48 hrs)
- contact dermatitis
Silvadene should be avoided in patients with?
- sulfa allergies (silvadene = silver sulfadiazine cream)
- pregnant patients
- newborns
1st line tx for MSSA and strep impetigo?
- cephalexin 250 mg qid x 7d, OR
- dicloxicillin 250 mg quid x 7d
- usually used with mupirocin as well
1st line management for outpatient MrSA
- TMP-SMX DS (1 po bid x 7d?)
- Doxycycline
1st line Tx for pseudomonas folliculitis (hot tub folliculitis):
- Cipro 500 mg bid x 7-14d
- will resolve on its own without Tx
True or false: OTC fungal drugs are effective for hair and nail fungal infections
False: good for skin and SSTI’s but not hair or nails.
Triazoles have (2 things):
- longer half life that ketoconazole
- less hormonal inhibition
1st line Tx for tinea capitis
Griseofulvin (Grifulvin, Gris-peg)
When should you NOT do arthrocentesis?
- cellulitis (high risk of inoculating the sterile joint with bacteria infecting the dermis)
- pts on anticoagulants
- prosthetic joint
Facts about synovial fluid
- similar to plasma
- hyaluronic acid
- no clotting factors
- acellular
- a semi-liquid connective tissue
Most common organism in a septic joint
S. aureus
True or false: a negative gram stain can be used to rule out infection of a joint.
False
True or false: a positive gram stain is not necessarily diagnostic of infection
False
What are rapidly progressive monoarticular Sx most indicative of?
Septic joint
Collection of pus with surrounding granulation
Abscess
Superficial form of cellulitis
Erysipelas
Presents with bright red spots that form smooth, hot plaques
Erysipelas
Red, hot, edematous, shiny plaque at port of entry
Cellulitis
Presents with sharply marginated tan or pink patches. Bacteria will glow red under Woods lamp.
Erythrasma
Cornybacterium minutissimum
Erythrasma
An abscess in the eccrine sweat glands or fat globules on fingertips
Felon
