Skin Flashcards
1
Q
Molluscum contagiosum
A
- Poxvirus (DNA virus) in children
- Bowl-shaped lesion filled with keratin, molluscum bodies (viral particles)
- Disseminates with HIV
2
Q
Rubeola (measles)
A
- Paramyxovirus (RNA)
- Cold Sx, conjunctivitis
- Koplik spots on buccal mucosa (white spots w/ erythematous base)
- …followed by maculopapular rash on head —> trunk —> extremities as T cells damage virus-infected endothelial cells
- Complications: giant cell PNA, acute appy, otitis media, encephalitis
3
Q
Rubella
A
- Togavirus (RNA)
- Forchheimer spots (red spots on posterior palate)
- Maculopapular rash lasting 3 days beginning at hairline, discrete lesions
- Painful postauricular lymphadenopathy
- Polyarthritis in adults
- Infection in first trimester may lead to congenital anomalies
4
Q
Erythema infectiosum
A
- Parvovirus B19 (DNA)
- Children
- Net-like erythema starting on cheeks (“slapped face” appearance)
- Polyarthritis in adults
5
Q
Roseola infantum
A
- HHV6 (DNA)
- Children
6
Q
Varicella zoster
A
- Positive Tzanck test (multinucleated giant cells)
- Children: Reye syndrome w/ ASA (encephalitis); PNA; cerebellitis
- Adults: PNA, hepatitis, encephalitis
7
Q
Hand-foot-and-mouth disease
A
- Coxsackievirus
- Young children
- Vesicular rash on hands, feet, mouth
8
Q
Toxic shock syndrome
A
- Staph aureus
- TSST toxin: superantigen
- Desquamating, sunburn-like rash
9
Q
Hidradenitis suppurativa
A
- Staph aureus, chronic
- Inflamed apocrine glands in axillae and groin
- Sinus tracts from abscesses
10
Q
Impetigo
A
- Often staph aureus
- Vesiculo-pustular rash begins on face, often with bullae
- Highly contagious
11
Q
Scalded skin syndrome
A
- Staph aureus with exfoliatin toxin
- Fever, large bullae
- Skin sloughs off, electrolytes lost
- Treat with nafcillin
12
Q
Staph aureus appearance and treatment
A
- Gram-positive coccus in clusters
- Bactrim, vancomycin
13
Q
Scarlet fever
A
- Strep pyogenes
- Erythematous sandpapery rash on tongue, face—>neck—>body (spares mouth)
- White exudate w/ red papillae on tongue later fades, leaving it beefy: strawberry tongue
- Rash disappears after 6 days, desquamation for up to 10 days after
- Increased risk of post-strep glomerulonephritis
14
Q
Strep pyogenes appearance
A
Gram-positive coccus in chains
15
Q
Erysipelas
A
- Strep pyogenes
- Type of cellulitis
- Orange peel-like surface with raised borders
- Face, lower extremities
- Penicillin G for extremities, vanco for face
16
Q
Leprosy
A
- Mycobacterium leprae (can’t be cultured)
- Tuberculoid type w/ intact cellular immunity: granulomas; positive lepromin skin test; localized skin lesions with nerve involvement (digital autoamputation, hypopigmented skin with anesthesia); treat with dapsone and rifampin
- Lepromatous type w/ impaired cellular immunity: many bacteria in foamy macrophages in subepidermal (Grenz) zone; negative lepromin skin test; leonine facies; dapsone, rifampin, and clofazimine
17
Q
Acne vulgaris
A
- Chronic inflammation of pilosebaceous unit
- Inflammatory type: abnormal keratinization of follicular epithelium, increased sebum production (androgen-dependent), Propionibacterium acnes converts sebum into irritating FAs
18
Q
Tinea capitis
A
- Trichophyton tonsurans: most common in black population, negative Wood lamp test (infects inner hair shaft)
- Microsporum canis and audouinii: most common in whites, positive Wood lamp test
- Circular areas of alopecia
- Oral terbinafine, NOT topical azoles
19
Q
Tinea corporis
A
- Trichophyton rubrum
- Raised border w/ central clearing
20
Q
Tinea pedis
A
- Trichophyton rubrum
- Macerated scaling rash b/w toes
- Diffuse plantar scaling (“moccasin” appearance) in elderly
21
Q
Tinea cruris
A
- Trichophyton rubrum
- Elevated borders WITHOUT central clearing
22
Q
Tinea unguium (onychomycosis)
A
- Trichophyton rubrum or mentagrophytes
- Nail is raised and discolored
- Nail plate is white, thick, crumbly
- Oral terbinafine (topical azoles do NOT work)
- Onychomycosis may also be caused by candida albicans
23
Q
Tinea versicolor
A
- Malassezia furfur
- Hyper- or hypopigmentation
- Accentuated by Wood lamp
- “Spaghetti and meatballs” appearance on KOH mount
- Single dose of oral ketoconazole
24
Q
Intertrigo
A
- Candida albicans
- Erythematous rash in body folds (“diaper rash”)
25
Q
Seborrheic dermatitis (dandruff)
A
- Malassezia furfur
- Associated w/ Parkinson’s, AIDS
- Scaly, yellowish, greasy dermatitis
- Scalp, eyebrows, nasal creases (“cradle cap” in neonates)
26
Q
Sporotrichosis
A
- Sporothrix schenckii
- Subcutaneous
- Thermal dimorph
- Traumatic implantation (ex. rose gardening, sphagnum peat moss)
- Chain of suppurating lymphocutaneous nodules
- Treat with oral itraconazole
27
Q
Cutaneous larva migrans
A
- Ancylostoma braziliense (nematode)
- Dog and cat hookworm; humans are intermediate host
- Contracted by children from cat/dog waste in sandboxes
- Larvae create serpiginous tunnels in skin
- Treat with albendazole
28
Q
Chiggers
A
- Small red mite
- Papular, urticarial, or vesicular rash
- Legs and areas of tight-fitting clothes
29
Q
Human itch mite (scabies)
A
- Sarcoptes scabiei or hominis
- Burrows between fingers; also at wrists, nipples, scrotum
- Females lay eggs, inducing pruritis
- In adults: intertriginous areas
- In infants: no burrows; rash on palms, soles, face, or head
- Permethrin cream
30
Q
Bedbugs
A
- Cimex lectularius
- Feed on human blood, active before dawn
- Allergic rxn to saliva causes wheals
32
Q
Solar lentigo
A
- Elderly
- Brown macules on sun-exposed areas due to increased # of melanocytes
33
Q
Vitiligo
A
- Black population
- Autoimmune destruction of melanocytes
- Associated w/ other autoimmune conditions
34
Q
Melasma
A
- Women
- Macular, hyperpigmented lesions lesions on face
- Exacerbated by OCPs, pregnancy, sunlight
- Treat w/ hydroquinone (bleaching agent)
37
Q
Seborrheic keratosis
A
- Adults >50 yrs
- Benign pigmented epidermal tumor
- “Stuck-on” appearance
- Leser-Trélat sign: rapid increase in keratoses from stomach adenocarcinoma
38
Q
Acanthosis nigricans
A
- Velvety, pigmented skin
- Neck, axilla, groin, under breasts
- Excess insulin
39
Q
Keratoacanthoma
A
- Males
- Crateriform tumor w/ central keratin plug grows over 4-6 weeks
- Sun-exposed area
- ? well-differentiated squamous cell carcinoma
40
Q
Epidermal inclusion cyst (follicular cyst)
A
- Epidermis of hair follicle
- Face, base of ears, trunk
- Produces keratin mixed w/ lipid-rich debris
41
Q
Pilar cyst (wen)
A
- Hair root sheath
- Scalp and face
- Cyst wall lacks stratum granulosum; keratin has laminated appearance
42
Q
Fibroepithelial polyp
A
- Elderly
- Skin tag on neck, upper chest, upper back
43
Q
Actinic (solar) keratosis
A
- Prolonged UV exposure
- Precursor of SCC
- Hyperkeratotic, pearly gray-white appearance of face, neck, dorsum of hands/forearms
- Topical 5-FU
44
Q
Basal cell carcinoma
A
- Chronic UV exposure
- Raised papule or nodule with central crater
- Inner canthus of eye, upper lip
- Locally aggressive, doesn’t metastasize
- Multifocal in origin
- Cords of basophilic-staining basal cells on biopsy
45
Q
Squamous cell carcinoma
A
- Risk factors: UV light, actinic keratosis, arsenic exposure, 3rd-degree burn, chronically draining sinus tract, immunosuppression
- Scaly to nodular ulcerated lesions
- Ears, lower lip, dorsal hands
- Minimal metastasis risk
- Topical 5-FU
46
Q
Ichthyosis vulgaris
A
- Autosomal dominant
- Keratinization defect: absent stratum granulosum, thick stratum corneum
- Hyperkeratotic, dry skin on palms, soles, extensor areas
47
Q
Xerosis
A
- Elderly
- Decreased skin lipids
48
Q
Eczema
A
- Acute: weeping, erythematous, vesicular rash
- Chronic: hyperkeratotic skin from scratching
- Atopic dermatitis: type I IgE hypersensitivity rxn; children: cheeks etc.; adults: hands, eyelids, elbows, knees
- Contact dermatitis: type IV hypersensitivity rxn
49
Q
Chronic cutaneous lupus erythematosus
A
- DNA-antiDNA immunocomplexes deposit in basement membrane
- Positive immunofluorescence
- Butterfly rash, alopecia
- Treat with antimalarials
50
Q
Pemphigus vulgarus
A
- IgG vs desmosomes b/w keratinocytes, type II hypersensitivity
- Vesicles and bullae on skin and oral mucosa
- Basal cells look like tombstones
- Nikolsky sign: outer epidermis easily separates from basal layer
51
Q
Bullous pemphigoid
A
- IgG vs basement membrane, type II hypersensitivity
- Subepidermal vesicles on skin and oral mucosa
- Negative Nikolsky
52
Q
Dermatitis herpetiformis
A
- IgA-antiIgA complexes (type III hypersensitivity) deposit in dermal papillae, causing subepidermal vesicles with neutrophils
- Strong association w/ celiac
- Treat with dapsone or sulfapyridine
53
Q
Lichen planus
A
- Pruritic, scaly, violaceous, flat-topped papules with Wickham striae; wrists & ankles
- Dystrophic nails, oral mucosa involved
- Women > men
- Slight SCC risk
- Associated with hep C
54
Q
Psoriasis
A
- HLA association
- Adolescents or ~60 yr olds
- Keratinocyte hyperplasia
- Aggravated by strep pharyngitis, HIV, drugs (lithium, beta blockers, NSAIDs)
- Thickened stratum corneum w/ nuclei retention and neutrophils; elongation of rete pegs of basal layer; extension of papillary dermis close to surface epithelium
- Auspitz sign: blood vessels in dermis rupture when scales are picked off
55
Q
Pityriasis rosea
A
- Herald patch: single, large, oval, scaly, rose-colored plaque on trunk (can be misdiagnosed as tinea)
- Later, papular eruption on trunk (“Christmas tree” distribution
- UV light therapy hastens resolution
56
Q
Erythema multiforme
A
- Type IV hypersensitivity
- Triggered by Mycolplasma pneumoniae, HSV, sulfonamides, penicillin, barbiturates, phenytoin
- Targetoid vesicles and bullae on palms, soles, extensor surfaces
57
Q
Stevens-Johnson syndrome
A
- Type IV hypersensitivity
- Erosions of mucous membranes, blistering of skin macules
58
Q
Toxic epidermal necrolysis syndrome
A
- Commonly drug-induced
- Can overlap with Steven-Johnson
- Necrosis and bullous detachment of epidermis and mucous membranes —> GI bleeding, resp failure, GU complications
59
Q
Erythema nodosum
A
- Inflammation of subQ fat
- Raised, erythematous, painful nodules
- Associations: coccidiodomycosis, histoplasmosis, TB, leprosy, strep pharyngitis, Yersinia, sarcoidosis, ulcerative colitis, pregnancy, OCPs
60
Q
Granuloma annulare
A
- Chronic
- Children, adult women
- Erythematous papules —> annular plaques
- Histiocytes around mucin
- Dorsal hands and feet; dissemination may occur with DM
61
Q
Porphyria cutanea tarda
A
- Uroporphyrinogen decarboxylase deficiency
- Wine-red urine with uroporphyrin I
- Photosensitive bullous skin lesions (metabolite depositions), hyperpigmentation, fragile skin, hypertrichosis
- Sunlight, hep C, alcohol, OCPs, iron
62
Q
Acne rosacea
A
- Inflammation of facial pilosebaceous units
- Demodex folliculorum mite
- Alcohol, stress, spicy foods exacerbate
- Sebaceous gland hyperplasia w/ enlarged nose
- Treat w/ topical metronidazole or systemic isotetrinoin or tetracycline
63
Q
Pyoderma gangrenosum
A
- Small papule that ulcerates and enlarges; violaceous border overhangs ulcer crater
- Often associated w/ systemic disease like Crohns, myeloproliferative disease, autoimmune diseases
- Neutrophil dysfunction
- May be triggered by trauma
- Treat w/ steroids, TNF-alpha inhibitors, cyclosporine
64
Q
Erythema toxicum
A
- Neonates
- Benign eruptions all over EXCEPT palms and soles
65
Q
Sebaceous hyperplasia
A
- Neonates
- Profuse yellow-white papules
66
Q
Milia
A
- Neonates
- Pearly white papules containing laminated keratin material
- Face, gingiva
67
Q
Miliaria
A
- Neonates
- Retained sweat in occluded glands
- Crystallina: pinpoint clear vesicles in large eruptions; associated w/ warmth or fever
- Rubra: small erythematous papulovesicles; also responds to cooling
68
Q
Mongolian spot
A
- Neonates w/ dark skin
- Blue-gray spots on buttocks, back, shoulders, legs
69
Q
Alopecia areata
A
- Young adults
- May have autoimmune or FHx association
- Hair loss in well-circumscribed round patches over weeks
- Treat w/ clobetasol, triamcinolone
