MUST KNOWS/ HIGH YIELD CONCEPTS Flashcards
What does the ectoderm give rise to?
Epidermis, melanocytes, nervous system
What structures are derived from the mesoderm?
Fibroblast, blood vessels, muscle, bone, dermis
How do merocrine glands release their contents?
Via exocytosis
What type of glands are eccrine and apocrine glands?
Merocrine glands
What characterizes holocrine glands?
Secretory cells burst
Which type of gland is sebaceous?
Holocrine gland
What type of gland releases contents directly on the skin surface?
Exocrine gland
What is unique about the distribution of sebaceous glands?
Only palms and soles are totally deprived of sebaceous glands
Where are the largest sebaceous glands found?
Nose
What is thalidomide used to treat?
Recurrent or persistent cases of erythema multiforme
What serum bicarbonate level indicates a poor prognosis in epidermal necrolysis?
Below 20 mM
What blood glucose level may indicate severity in epidermal necrolysis?
Above 14 mM
What is the most common complication during the acute phase of epidermal necrolysis?
Sepsis
What is the hallmark of ichthyosis?
Scale
What is ulerythema ophryogenes associated with?
Scarring alopecia on eyebrows; normal scalp and eyelash hair
What condition is characterized by worm-eaten and honeycomb appearance?
Atrophoderma vermiculatum
What are angiokeratomas a cutaneous hallmark of?
Fabry Disease
In what context does pustular PG occur?
Exacerbation of acute IBD (usually UC)
What differentiates vegetative PG from other variants?
Not usually associated with systemic disease
What virus is associated with trichodysplasia spinulosa?
Polyomavirus
What is the most common type of porokeratosis?
Disseminated superficial actinic porokeratosis
What is the primary lesion of pemphigus vulgaris?
Flaccid blister
Which mucous membranes are most affected by pemphigus vulgaris?
Oropharyngeal cavity and nasal mucosa
What is a common presenting sign of pemphigus vulgaris?
Painful mucous membrane erosions
What malignancies are most commonly associated with paraneoplastic pemphigus?
Non-Hodgkin lymphoma, chronic lymphocytic leukemia, Castleman disease
What characterizes the classic form of bullous pemphigoid?
Large, tense blisters on normal skin or erythematous base
Major MMP and bullous pemphigoid autoantigen
BP 180
What is EBA?
Classical presentation of epidermolysis bullosa acquisita
What is the most severe phenotype of junctional epidermolysis bullosa?
Severe generalized JEB
What is the most common subtype of recessive dystrophic epidermolysis bullosa?
Severe subtype
What may low-dose methotrexate precipitate in rheumatoid arthritis patients?
Erythema and enlargement of preexisting rheumatoid nodules
What is the characteristic eruption of Adult-Onset Still Disease?
Salmon-colored, macular or slightly papular eruption concurrent with fever spikes
What is scleredema?
Rare condition affecting men and women equally
What is the most specific clinical finding in acanthosis nigricans?
Central keratotic core
Which subtype of Ehlers-Danlos syndrome is most clinically significant?
Vascular subtype
What is Fabry disease?
Inherited X-linked lysosomal storage disorder caused by deficient α-galactosidase A activity
What defines abnormal hair loss?
Daily telogen hair loss more than 100
What types of eruptions are associated with phototoxicity?
Vesicular and bullous eruptions
What is a characteristic finding of hyperimmunoglobulin E syndrome in infancy?
Papulopustular dermatitis of the face and scalp
What indicates a poor prognosis in peripheral artery disease?
Decreased or absent pulses distal to the stenotic arterial segment
What is the most sensitive indicator of intrahepatic cholestasis of pregnancy?
Elevation in serum bile acids
What is a cardinal feature of pustular psoriasis?
Rapid resolution of symptoms after delivery
What are first-line therapies for pustular psoriasis of pregnancy?
Cyclosporine and infliximab
When does PEP typically occur?
In primigravidas during the last trimester of pregnancy
What is the high-risk area for psoriatic arthritis?
Scalp and intergluteal psoriasis
What is the most pronounced histologic change in aged skin?
Flattening of the dermal–epidermal junction and loss of rete ridges
What syndrome involves nevus comedonicus with noncutaneous findings?
Nevus comedonicus syndrome
What are the most common extracutaneous features of epidermal nevus syndrome?
Ocular, neurologic, and skeletal systems
What characterizes steatocystoma?
Sebaceous duct cyst with a waxy, eosinophilic cuticle lining
Where do trichilemmal cysts arise from?
Outer root sheath of the hair follicle
What is the most important etiologic factor for actinic keratoses?
Long-term and cumulative ultraviolet (UV) radiation exposure
What is epidermodysplasia verruciformis (EV)?
Inherited skin condition with high susceptibility to HPV infection
What types of HPV are associated with anal intraepithelial neoplasia?
Types 16, 18, 31, and 33
What is the strongest risk factor for leukoplakia?
Tobacco
What is erythroplakia known for?
Greatest potential to harbor or become oral squamous cell carcinoma
What pathway is activated in all basal cell carcinomas?
Hedgehog signaling pathway
What drug was approved for locally advanced or metastatic basal cell carcinoma?
Vismodegib
What is sonidegib used for?
Locally advanced basal cell carcinomas
What is the most important environmental risk factor for squamous cell carcinoma?
Ultraviolet radiation (UVR)
What clinical features correlate with histologically proven dysplastic nevi?
Nevus size and irregular borders
What is the most concerning complication associated with dysplastic nevi?
Melanoma
What is acral lentiginous melanoma (ALM) not associated with?
Sun exposure
Where does subungual melanoma generally arise from?
Nail matrix
What is the most frequent targetable mutation in acral melanoma?
BRAF mutation (21%)
What is associated with higher local recurrence in desmoplastic melanoma?
Higher local recurrence but lower nodal metastatic rates
What is uveal melanoma?
Most common primary intraocular malignancy
What type of sun exposure is most important in melanoma causation?
Periodic, intense sun exposure during childhood and adolescence
What type of sun exposure is associated with lentigo maligna?
Cumulative sun exposure
What are the two most common early characteristics of melanoma noticed by patients?
Change in color and increase in size (or a new lesion)
What mutation is most common in melanomas of sun-exposed skin?
BRAF V600 mutation
What is the most frequent mechanism of acquired therapeutic resistance in melanoma?
Reactivation of the MAPK pathway
What defines Langerhans cell histiocytosis (LCH)?
Rare, heterogeneous neoplasm of dendritic cells
What mutation is found in 60% of LCH biopsy specimens?
V600E mutation in BRAF
What organ systems are most commonly affected by LCH?
Bone, skin, lymph nodes, lungs, CNS
What are at-risk organs for LCH?
Hematopoietic system, liver, spleen
What might purpura with nail involvement indicate in LCH?
Poor prognostic sign
What is the most sensitive marker for LCH?
Immunohistochemical staining with CD207
What is a typical finding in LCH cells?
Presence of Birbeck granules in the cytoplasm
What defines a cure in cutaneous T-cell lymphoma (CTCL)?
Freedom from disease for 8 years off all therapy
What is brentuximab vedotin?
Anti-CD30 monoclonal antibody
What is mogamulizumab?
Defucosylated anti-CCR4 monoclonal antibody
What is plexiform neurofibroma associated with?
Neurofibromatosis type 1 (NF-1)
What is lipomatosis of nerve characterized by?
Proliferation of adipose and fibrous tissue within the epineurium and perineurium
What does hibernoma represent?
Benign neoplasm of brown fat
What laboratory findings indicate essential fatty acid deficiency?
Decreased linoleic and arachidonic acids, elevated 5,8,11-eicosatrienoic acid
What are the four Ds of pellagra?
Dermatitis, diarrhea, dementia, death
What is referred to as ‘Casal’s necklace’?
Dermatitis affecting the upper central portion of the chest and neck
What is acrodermatitis enteropathica?
Inherited defect in the intestinal zinc transporter ZIP4
How can zinc status be measured?
Serum zinc or alkaline phosphatase levels
What is Menkes disease?
X-linked disorder of intestinal copper transport
What is a characteristic appearance of Menkes disease?
Cherubic appearance with depressed nasal bridge, ptosis, reduced facial movements
What type of infection is noma?
Polymicrobial infection
What is the first-line testing for porphyria cutanea tarda (PCT)?
Measurement of total plasma or urine porphyrins
What treatments are effective for PCT?
Phlebotomy or low-dose hydroxychloroquine
What is erythropoietic protoporphyria?
Third most common porphyria and most common in children
What mutation causes X-linked protoporphyria?
Gain-of-function mutation of ALAS2
What are the four acute porphyrias characterized by?
Neurologic symptoms occurring as intermittent acute exacerbations
What is the most common acute hepatic porphyria worldwide?
Acute intermittent porphyria
What are tuberoeruptive xanthomas associated with?
Type III disorders
What is the first-line pharmacotherapy for lowering LDL-C?
Statins
What is the ocular finding most commonly associated with Fabry disease?
Cornea verticillata
What is a classical feature of Fabry disease?
Reduced sweating
What is the most common type of calcinosis cutis?
Dystrophic calcification
What are the most commonly affected sites of gout?
First metatarsophalangeal joint and ankle
What are the most common features of dyskeratosis congenita?
Triad of reticulated hyperpigmentation, dystrophic nails, mucosal leukoplakia
What are the features of ectodermal dysplasia?
Hypotrichosis, hypohidrosis, hypodontia
What is the most common manifestation of Wiskott-Aldrich syndrome?
Bleeding diathesis
What heart manifestation is most common in systemic lupus erythematosus?
Pericarditis
What is the most common intrathoracic manifestation of sarcoidosis?
Bilateral hilar adenopathy
What is the most common pulmonary manifestation of rheumatoid arthritis?
Interstitial lung disease (ILD)
What bilirubin level indicates jaundice?
Above 3
What are Kayser-Fleischer rings associated with?
Wilson disease
What is necrolytic migratory erythema a hallmark of?
Glucagonoma
What contributes to thrombus formation?
Virchow triad: abnormal blood flow, vessel wall injury, blood hypercoagulability
What agents are associated with squamous cell carcinoma (SCC)?
Azathioprine, coal tar, cyclosporine, mineral oil, soots
What factors are linked to both SCC and basal cell carcinoma (BCC)?
Arsenic
What is the most important risk factor for SCC?
Solar radiation
What is the main Streptococcus strain in Behçet disease?
Streptococcus sanguinis
What is the major microscopic finding in Behçet disease?
Immune-mediated occlusive vasculitis
What role does IL-8 play in Behçet disease?
Important in inflammatory response and sensitive marker of disease activity
What are the recurrent symptoms of Behçet disease?
Recurrent oral aphthous and genital ulcers
What is the dominant flora of the oral mucosa in patients with Behçet disease?
Streptococcus sanguinis
This strain appears to be a provoking factor for the initiation of Behçet disease.
What is the major microscopic finding in active Behçet disease?
Immune-mediated occlusive vasculitis
Which interleukin plays an important role in Behçet disease?
IL-8
IL-8 can be released by endothelial cells and is a sensitive marker of disease activity.
What are the most frequently observed mucosal manifestations in Behçet disease?
Recurrent oral aphthous and genital ulcers
What percentage of Behçet disease cases present with oral aphthous ulcers?
More than 80%
What is the major cause of morbidity in patients with Adamantiades–Behçet disease?
Ocular involvement
What is the most diagnostically relevant lesion in Behçet disease?
Posterior uveitis (retinal vasculitis)
What type of arthritis is characteristic of Behçet disease?
Nonerosive, asymmetric, sterile, seronegative oligoarthritis
What are the characteristic histopathologic features of Adamantiades–Behçet disease?
Vasculitis and thrombosis
Which blood vessels are primarily damaged in Kawasaki disease (KD)?
Medium-sized muscular arteries, especially coronary arteries
What treatment reduces coronary artery abnormalities in Kawasaki disease when given in the first 10 days of fever?
Intravenous immunoglobulin (IVIG) and aspirin
What is the prevalence reduction of coronary artery abnormalities with IVIG plus aspirin compared to aspirin alone?
From 25% to 5%
What is a common association with granulomatous pigmented purpura?
Hyperlipidemia
What is the histopathologic hallmark of mixed cryoglobulinemia?
Leukocytoclastic vasculitis
What is the most common cause of death in HCV patients with mixed cryoglobulinemia?
Infection
For which tumors is Mohs surgery most effective compared to standard excision?
Aggressive histologic features, Diameter > 2cm, Tumors on H zone
What are the four factors most strongly associated with adverse outcomes in squamous cell carcinoma (SCC)?
- Diameter > 2 cm
- Depth of invasion below SQ
- Perineural invasion
- Poor histologic differentiation
What are the Mohs high-risk areas for squamous cell carcinoma?
- H zone of the face
- Genitalia
- Hands
- Feet
- Ankles
- Nipple
- Areola region
What is the primary treatment for venous malformations (VM)?
Percutaneous intralesional sclerotherapy
What is the most common cause of infective endocarditis (IE) related to oral cavity procedures in low-income countries?
Rheumatic heart disease
What are the classic presentations of acute limb ischemia secondary to vessel thrombosis or embolism?
- Severe pain at rest
- Pallor
- Pulselessness
- Paresthesias
- Paralysis
In native valve infective endocarditis, which patient population is most affected?
IV drug users
What is the common early (<2 months) pathogen in prosthetic valve infective endocarditis?
Streptococcus and Staphylococcus aureus
What is the 5-year mortality rate for infective endocarditis?
~40%
What is the prognosis for right-sided infective endocarditis in IV drug users?
Better prognosis (5-9% mortality)
What is a key short-term prognostic factor in infective endocarditis?
Neurologic failure
Sepsis with erythroderma suggests which type of toxic shock syndrome (TSS)?
Staphylococcal or streptococcal TSS
What are the key skin findings in disseminated intravascular coagulation (DIC)?
Diffuse noninflammatory retiform purpura
What is the extreme form of DIC seen in meningococcal sepsis?
Waterhouse-Friedrichsen Syndrome
What organism requires cysteine-supplemented blood agar for culture?
Francisella tularensis
What is the hallmark of Yersinia pestis infection?
Exquisitely tender regional lymphadenopathy (buboes)
What are the primary risk factors for peripheral artery occlusive disease (PAOD)?
Diabetes mellitus and smoking
What is the recommended diagnostic test to assess for peripheral artery disease (PAD)?
Ankle-brachial index (ABI)
What is considered an abnormal ABI value?
Less than or equal to 0.90
What is the major risk factor for atheromatous embolism?
Atherosclerotic disease of the thoracic or abdominal aorta
What typically occurs 1 to 3 weeks following group A streptococcal pharyngitis?
Poststreptococcal glomerulonephritis
What organism mimics ulceroglandular tularemia but causes necrotizing cellulitis?
Pasteurella multocida
What are common initial complaints in peripheral artery disease?
- Claudication of the foot or lower calf
- Digital cyanosis or gangrene
- Rest pain
What is the first-line treatment for rat-bite fever caused by Streptobacillus moniliformis?
Amoxicillin-clavulanate
What is the characteristic agar for culturing diphtheria?
Löffler or tellurite agar
What is the triad of symptoms diagnostic of clostridial myonecrosis?
- Soft-tissue crepitus
- Severe pain
- Tachycardia disproportionate to fever
Who is more commonly affected by lupus vulgaris?
Females
What test may be negative in early active tuberculosis or indeterminate in immunocompromised and children?
Quantiferon TB Gold test
What is the single greatest risk factor for disseminated meningococcal disease?
Lack of bactericidal antibodies
What is the initial presentation of ecthyma gangrenosum?
Painless, infarcted gunmetal gray macule or papule with surrounding erythema
how many classifications are there in Hamilton-Norwood Classification of male pattern baldness?
VII
How many grades are there in Ludwig’s pattern of hair loss in females?
III
