*Dermatology Flashcards
Neurofibromas
- multiple sessile, fleshy tumors
- non-tender, move w/ skin on exam
- assoc w/ neurofibromatosis type I (Von Recklinhausen dz)
Von Recklinhausen disease
key derm findings
aka: neurofibromatosis type I
Key Findings
- cafe-au-lait macules
- axillary and inguinal freckling
- neurofibromas
- Lisch nodules
AD disorder results from a mutation in NF1 gene coding for neurofibromin
LISCH NODULEs
-
hamartomas of the iris that do not affect vision
- Hamartoma: benign, noncancerous tumorlike malformation made up of an abnormal mixture of cells and tissues found in areas of the body where growth occurs
- associated w/ Neurofibromatosis Type I
Beau’s Lines
- lines/indentations in the nail that result from delayed growth
- usually due to nutritional deficiency, or can be from injury or severe illness
- assoc. w/ Systemic Lupus Erythematosus
what % of nail is subungual hematoma for nail bed laceration to be considered?
25% or more of the nail
matrixectomy:
contraindication
infectious process
- infxn will drastically decrease effectiveness of matrixectomy
- insult to tissue in presence of infectious process may facilitate a deeper infxn → possibly an osteomyelitic one
pityriasis rubra pilaris
- rare with reddish orange lesions involving hair follicles, mildly pruritic
- affects palms/soles w/ yellowish scale
- Islands of sparing – even when most of the body is red (erythrodermic)
- a papulosquamous disorder (inflammatory rxn)
- Most common is classic adult onset which _begins at scalp and moves caudally_
- _Affects palms/soles with a yellowish scale_ – well demarcated “PRP sandal”
pityriasis rosea
- “salmon-colored lesion and peripheral collarette”
-
*Herald patch - 2-10 cm patch anywhere on body
- misdiagnosed as ringworm
- “Christmas tree” appearance on the back
differential diagnosis for pityriasis rosea
secondary syphilis
- Comes weeks later after painless chancre**, **may resemble with papulosquamous lesion (palms/soles involved)
- Get sexual history, VDRL or RPR
- History – painless chancre, fevers, myalgias, lymphadenopathy
- Secondary syphilis very common on plantar foot in some patients with localized disease
lichen planus
- acute eruption of itchy papules**, will usually settle in a few months, **start on inside of arms/legs and go up
- associated w/:
- Wickham’s striae - fine lacy network of lines on top of papules
- Koebner’s phenomenon
- can be assoc. w/:
- hepatitis C virus infxn
- SLE
- ulcerative colitis
- alopecia
- areata
- vitiligo
- dermatomyositis
- morphea
- lichen sclerosis
- myasthenia gravis
6 P’s of Lichen Planus
- Planar (flat-topped)
- Purple
- Polygonal
- Pruritic
- Papules
- Plaques
Koebner phenomenon
appearance of new skin lesions on previously unaffected skin secondary to trauma
Wickham’s Striae
fine lacy network of lines on top of papules
necrotizing fasciitis
- deep infxn of the SubQ tissue that causes progressive destruction of the fascia and fat
- infxn spreads through muscle fascia due to its relatively poor blood supply
- histo features:
- thrombosis of blood vessels
- extensive tissue destruction
- abundant bacteria spreading along fascial planes
- infiltration of acute inflammatory cells
nec fasciitis
early stages → progression
- thrombosis of small blood vessels and destruction of superficial nerves → development of anesthesia → affected area is usually characterized by erythema, swelling, warmth, and tenderness
- over several days, skin can rapidly change from red-purple to patches of blue gray
- skin breakdown can occur w/in 3-5 days w/ formation of bullae that contain thick pink or purple fluid
nec fasciitis
treatment
- only tx is surgical exploration and debridement of necrotic tissue, and delays in tx are assoc. w/ high morbidity and mortality
- broad-spectrum Abx regimens incl: carbapenem or beta-lactam-beta-lactamase inhibitor with clindamycin and an agent w/ activity against MRSA
erythema nodosum
etiology
- occur as a delayed hypersensitivity response to a number of factors:
- oral contraceptives
- strep infxn
- sarcoidosis
- ulcerative colitis
- tuberculosis
- fungal infections
Erythema nodosum
define
children and young adults, multiple tender erythematous nodules on anterior tibia** (sometimes on forearms), **inflammatory process of fat (panniculitis)
- Color change – red 🡪 purple 🡪 yellow-green
- Biopsy – most fully developed central portion, incisional type of biopsy
- Causes – strep infection, drugs, sarcoidosis, TB, IBD
- Treatment – bed rest and oral analgesics
- Will resolve in a few days, but 77% infection related resolve in 7 weeks, 30% idiopathic may last up to 6 months
characteristic of
LICHENIFICATION
common consequence of pruritic skin disorders, including atopic dermatitis
characterized by:
- skin thickening and hardening
- exaggeration of normal skin lines
- hyperpigmentation
- scaling and pruritis
Most commonly found on anterior aspect of ankles and may be the result of repetitive scratching or rubbing
filariasis
- mosquito-borne parasite that can result in alterations to the lymphatic system → pain, lymphedema, and severe disability
- round-worm parasite that lives 6-8 years, producing millions of immature larvae
- tx w/ albendazole and diethylcarbamazine
-
Sxs:
- lymphedema
- elephantiasis
- scrotal swelling in men can all occur, usually after a long latency
- Can present after travel to an endemic area, may be unilateral
list some primary causes of lymphedema
- neurofibromatosis
- yellow nail syndrome
- distichiasis lymphedema syndrome
all result from congenital defects in the lymphatic system
distichiasis lymphedema
syndrome
- a condition that affects the normal function of the lymphatic system
- sxs:
- puffiness or swelling of the legs and feet
- some patients may have spinal cysts
- **growth of extra eyelashes* (distichiasis), ranging from a few extra eyelashes to a full extra set on both the upper and lower lids; these grow out of its inner lining (not along the edge of the eyeball)
cause and treatment?
trichophyton mentagrophytes
- the most common causative organism in white superficial onychomycosis
- characterized by dull white spots on the surface of the nail plate of one or several nails;
- if not treated, the diseased area will spread centrifugally and involve the entire nail plate;
- white areas can be scraped to yield a chalky scale for examination
- Tx: Terbinafine for dermatophyte onychomycosis
lesion is suspicious for malignant melanoma
- asymmetry, border irregularity, diameter greater than 6 mm
- more likely to be dark black or blue or to have an irregular variation in color
- surgical excision is indicated, w/ wide margins and excision of related lymph nodes
- exposure to UV is a critical factor in development, but it does not have a direct relationship with amount of sun exposure
relationship b/w UV light and cancer
UV radiation can:
- suppress the skin’s immune system
- induce melanocyte cell division and free radical production
- it can damage melanocyte DNA
layers of the epidermidis from
most superficial to most deep
“Come Let’s Go See, Babe”
- Horny (stratum corneum) – most superficial layer
- Stratum lucidum** (**ONLY IN PALMS AND SOLES)
- Granular (stratum granulosum)
- Prickle (stratum spinosum)
- Basal (stratum germinativum) – deepest layer
what is the basement membrane
dermal - epidermal interface
(area of research interest because problems here can cause visible skin disease)
dermis anatomy
- Separated into papillary and reticular
- Lots of collagen in reticular layer
- Place where hair and glands begin
- Temperature regulation through control of cutaneous blood flow and sweating
- Mechanical protection of underlying structures
subcutaneous / subcutis
anatomy
- Consists of spongy connective tissue with energy-storing adipocytes (fat cells)
- The fat content of the subcutis is not the same in all body regions and differs in men and women
Zero fat in and around nail tissue
differences between hair and nails
when do nails begin to grown in utero?
onychocytes begin to develop
10<u>th</u>-17<u>th</u> week in utero
what forms the nail plate?
formed by mostly nail matrix – some contribution from nail bed, shape contributed from matrix and phalanx
differences between:
apocrine and eccrine
glands
Nikolsky sign
a skin finding in which the top layers of the skin slip away from the lower layers when rubbed
staphylococcal scalded skin syndrome
Bullous pemphigoid
Staphylococcus Toxic Shock Syndrome
Erythema Multiforme
toxic epidermal necrolysis
exanthematous reaction
(“morbiliform” eruption on trunk/ extremities)
Urticaria
angioedema
fixed drug eruption rash
DRESS Syndrome
“Drug Reaction w/ Eosinophilia and Systemic Symptoms”
Erythema Multiforme
Urticaria
polyarteritis nodosa
erythema nodosum
polyarteritis nodosa
Livedo reticularis
?
Seborrheic dermatitis
Seborrheic dermatitis
Allergic contact dermatitis
Irritant Contact Dermatitis
Psoriasis
Psoriasis
Psoriasis
Stevens-Johnson Syndrome
on the spectrum of immune-mediated reaction that can be from:
erythema multiforme → SJS → toxic epidermal necrolysis
Porphyria Cutanea Tarda
Porphyria Cutanea Tarda
pemphigus vulgaris
atopic dermatitis
Lichen Simplex Chronicus
Allergic Contact Dermatitis
Psoriatic nails
Pustular Psoriasis
Guttate Psoriasis
Guttate Psoriasis
Plaque Psoriasis
Psoriasis
Melanoma
Tinea Corporis
(ringworm)
Seborrheic Keratosis
Kaposi’s Sarcoma
Kaposi’s Sarcoma
Lentigo Melanoma
Superficial Spreading Melanoma
Melanoma
Nodular Melanoma
Benign Melanocytic Nevi
Benign Melanocytic Nevi
Benign Melanocytic Nevi
Acral Lentiginous Melanoma
(tends to occur on palms of hands and soles of feet, *OR under nail plates)
nodular basal cell carcinoma
Keratoacanthoma
Exophytic Squamous Cell Carcinoma
Nodular Squamous Cell Carcinoma
Basal Cell Carcinoma
Nodular Basal Cell Carcinoma
Pigmented Basal Cell Carcinoma
Ulcerating Basal Cell Carcinoma
Superficial Multicentric Basal Cell Carcinoma
Mycosis Fungoides (Cutaneous T-Cell Lymphoma)
Mycosis Fungoides (CTCL)
Acne Rosacea
SLE Diagnostic criteria
(4-Skin-RASHNIA)
Systemic Lupus Erythematosus
Acrochordon
(Skin Tags)
Candida Albicans
(Intertrigo)
Impetigo
Varicella
Molluscum Contagiosum
Plantar Wart
Assoc. w/ HPV
Painful at pressure points
Verruca Vulgaris
(“common wart”)
cauliflower lesion with red/black dots (thrombosed capillaries)
disrupts finger prints
4 HPV wart types?
Condyloma Acuminata is anogenital warts
Herpetic Whitlow
(HSV Infection)
Shingles
(caused by ZVZ)
Pityriasis Rosea
Pityriasis Rosea
(Herald Patch - salmon-colored lesion with peripheral collarette)
Pityriasis
(Tinea Versicolor)
Malasezzia Globosa - spaghetti and meatballs hyphae appearance
Pityriasis
(Tinea Versicolor)
Vitiligo
Cellulitis
Erysipelas
by Strep Pyogenes!
Cellulitis versus Erysipelas
Dermatomyositis
(Gottron’s Sign)
