Dermatology Flashcards
Erythema Nodosum presentation and common causes
Presents as a sore stinging nodules on the shins, MC caused by strep infections or sarcoidosis
“Stuck on” lesion with greasy appearance
Seborrheic keratosis
Alopecia Areata vs Androgenic Alopecia
Alopecia Areata: immune-mediated hair loss coming on in PATCHES with “exclamation point hairs”; often other immune comorbidities and nail manifestations ; steroids are treatment
Androgenic ALopecia: progressive loss of the terminal hairs, hiring THINNING; due to low DHT levels ; treat with Minodixil or finasteride
What is the atopic triad?
- atopic dermatitis (eczema)
- asthma
- allergic rhinitis
Clinical manifestations of atopic dermatitis (eczema)
- Pruritus
- red, blistery lesions in FLEXOR surfaces, scaling
- dermatographism
What is dermatographism ?
localized hives when the skin is stroked
What is Nummular eczema?
sharply defined COIN SHAPED lesions on dorsum and extensor surfaces
Treatment for atopic dermatitis
Avoid triggers, topical steroids and antihistamines
Dyshidrosis (aka pompholyx)
Puritic “tapioca-like” tense vesicles on the soles, palms, fingers in response to water such as sweat, humid weather, or nikel
What is lichen simplex chronic?
Skin lichenification due to chronic itching in eczema patients
Treat with topical steroids
Clinical manifestations of Lichen Planus
-5 P’s: Purple, polygonal, planar, puritic, papillose with WICKHAM STRIAE (white lines) found on flexor surfaces, skin, mouth, scalp, genitals
Pathophis of lichen planus
idiopathic cell- mediated immune response with a high incidence in Hep C.
-Treat with topical steroids
What is Koebner’s phenomenon and what is it seen in?
New lesions at sites of trauma seen in lichen planus and psoriasis
What is psoriasis?
Chronic mulisystem inflammatory immune disorder that results in keratin hyperplasia
Clinical manifestations of plaque soriasis
- Rasied red lesions with thick silver scaling
- MC on EXTENSOR surfaces
- nail pitting and auspitz sign
What is Auspitz sign?
punctate bleeding with removal of plaques in psoriasis
Psoriasis management
Mild: topical steroids
Severe: Phototherapy, methotrexate
Other types of psoriasis (not including plaque)
- Pustular: deep yellow pustules evolving into red merciless on palms/soles
- Guttate: small discrete red lesions with fine scales
- Inverse: no scaling
- Erythrodermic: generalized rash over most of the skin (worst type)
- Psoriatic arthritis: pencil in cup deformity
Pityriasis (tinea) versicolor Hallmarks
- Overgrowth of yeast Malassezia furor
- Hyper/hypo-pigmented round merciless with fine scaling, grows in patches , this part of skin fails to tan
- KOH prep shows hyphae & spores “spaghetti & meatball”
- Woods lamp exam
-Treat with topical antifungals
Topical antifungals
Selenium sulfide
Sodiom sulfacetamide
What is seborrheic dermatitis?
hypersensitivity to malassezia furfur yeast that occurs in areas of high sebaceous gland functioning
- Presents as cradle cap in infants and DANDRUFF in adults
- Treat with topical antifungals
5 types of hypersensitivity reactions
Type 1: Ig-E mediated, acuate urticaria and angioedema
Type 2: cytotoxic antibody mediated causing cell lysis
Type 3: immune antibody-antigen complex
Type 4: Delayed, cell mediated (erythema multiforme, morbiliform rash)
Type 4: non-immunologic
What is the MC presenting rash in a drug eruption?
Exanthematous/Morbiliform Rash: generalized bright red macules and papillose that coalesce to form plaques.
-typically 2-14 days after drug taken
Different presentations of cutaneous drug eruptions
- Morbiliform rash (MC)
- Urticarial (2nd MC) (type 1)
- Erythema multiform (type 4)
Drugs that MC cause erythema multiform reaction
- sulfa
- penicillians
- phenobarbitol
- dilantin
Pathophysiology of urticaria
mast cells release histamine causing vasodilation and edema of dermis
Outside of medications, what illnesses are associated with erythema multiforme?
HSV (MC)
mycoplasma
S. pneumo
What is the difference between erythema multiforme minor and major
MINOR: target lesions with no mucosal membrane involvement
MAJOR: target lesions with involvement of at least 1 mucus membrane, but there is no epidermal detachment (that would be SJS)
Steven-Johnson Syndrome
MC after drug reaction that develops less than 10% BSA sloughing with epidermal detachment (Nikolsky sign), at least 1 mucus membrane involved
Toxic Epidermal Necrolysis
MC after drug reaction that develops over 30% BSA sloughing with skin necrosis and epidermal detachment (+ nikolsky sign) ; at least 1 muscus membrane involved
What is the pathophysiology behind acne vulgarism?
- increased sebum production due to increased androgen activity
- Clogged sebaceous glands
- P. Acne overgrowth
- Inflammatory response
3 clinical manifestations of acne vulgaris
- Comedones
- open=blackhead, partial block
- closed=whitehead, complete - Inflammatory: pustules surrounded by inflammation
- Nodular or cystic acne:heals with scarring
Management of Mild Acne
- topical retinoids
- benzoyl peroxide (decreased P. acne)
- OCP (decrease androgens)
Management of moderate acne
- mild treatment PLUS oral antibiotics
- Doxycycline, Minocycline
Management of severe acne
-all other treatments plus
Isotretinoins
-these increase Trigs, psych effects, teratogenic
What is the pathophysiology of Rosacea?
Persistant vasomotor instability of unclear etiology
Roasacea treatment
Metronidazole
What is actinic keratosis?
MC premalignant skin condition
-leads to squamous cell carcinoma
Hallmarks of actinic keratosis
-scaly hyper pigmented sandpaper lesions in sun exposed areas
What is seborrheic keratosis?
MC benign skin tumor
Clinical manifestations of seborrheic keratosis
small papule with a velvety warty lesion
“greasy stuck on appearance”
What lesions will whiten with acetic acid application?
HPV
Condyloma Acuminata
genital warts
HPV 6,11
Painless papule that evolve into soft fleshy cauliflower-like lesions
Vitiligo
Autoimmune destruction of melanocytes resulting in skin depigmentation
What is Kaposi Sarcoma?
- Connective tissue cancer found in immunocompromised patients
- Caused by Human herpesvirus 8
- Violet red/brown plaque like lesions
- HAART therapy is treatment
3 types of impetigo
- Nonbullous: vesicles & pustules, honey colored crust; Staph MC. GABHS 2nd
- Bullous: vesicles form large bullae, Staph MC
- Ecthyma: ulcerative, GABHS
Impetigo management
- Mupirocin (Bactroban) cream
- If severe you can use antibiotics such as Cqphalexin or clindamycin
Treatment of folliculitis
Topical mupirocin
Layers of the skin impacted by cellulitis
dermis and subcutaneous tissue
**not well demarcated!
MC causative organisms of cellulitis
S. Aureus MC
-GABHS (strep pyogenes)
Erysipelas
- Caused by GABHS
- WELL DEMARCATED, often on the face
- Treat with PCN
Lymphangitis
spread of cellulitis through the lymph vessels leaving streaking
Medical management of cellulitis
Cephalexin; dicloxacillan
What antibiotic should be used in a cat bite
Augmentin
Doxy if pen allergic
Clinical manifestations of scabies
- intensely pruritic lesions with linear burrows often in the web spaces
- papules on scrotum, glans or penile shaft, body folds are pathopneumonic for scabies
Scabies treatment
Permethrin topical cream
-ivermectin if extensive
What is pediculosis
Lice
What are the white oval shaped egg capsules at the base of hair shafts in those infected with lice called?
Nits
What is the treatment for lice?
Permethrin
