Dermatology Flashcards

1
Q

DDx of atopic dermatitis

A

seborrheic dermatitis, scabies, psoriasis, nutritional deficiencies (zinc), immunodeficiency, cutaneous lymphoma

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2
Q

Which bacteria/viruses can cause superinfection of eczema?

A

Staph aureus, group A strep, candida, viral (HSV, coxsackie, molluscum)

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3
Q

First-line treatment of atopic dermatitis?

A
  • Bathing 1X per day 5-10 min with lukewarm water (frequency unclear). No oils
  • Pat dry, apply steroids then vaseline. Atarax 2-3 times per day for itch
    Hydrocortisone 1% ointment
    Betamethasone valerate 0.05% ointment for the body
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4
Q

Treatment of scabies?

A

5% permethrin overnight + repeat 1 week later, treat household contacts, sheets
Apply to entire body in kids < 2 (neck down in kids and adults)
< 8 weeks old: precipitated sulfur in petroleum

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5
Q

Which organism causes “hot tub folliculitis”?

A

Pseudomonas

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6
Q

Which organism causes furunculosis? Treatment?

A

MRSA
Tx with I&D, (antibiotics are controversial). Recurrence is common, may need decolonization for MRSA with chlorhexidine washes or intranasal mupirocin

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7
Q

Which organism causes bullous impetigo?

A

Staph aureus

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8
Q

What is Nikolsky sign? What conditions is it seen in?

A

skin peeling when rubbed

Seen in SSSS, SJS/TEN

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9
Q

Treatment of SSSS?

A

Tx with oxacillin or beta lactamase-resistant abx (can use cefazolin), add clindamycin for toxin (+vanco if very unwell for MRSA)

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10
Q

List 5 bacteria that cause soft tissue infection in exposure to water? Which organism causes a bullous infection?

A
Aeromonas species
Edwardsiella tarda
Erysipelothrix rhusiopathiae
Vibrio vulnificus *BULLOUS
Mycobacterium marinum
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11
Q

Which organisms cause tinea capitis?

A

microsporum canis and trichophyton tonsurans

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12
Q

Treatment of kerion?

A

terbinafine/griseofulvin and steroids

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13
Q

DDx of hair loss

A

Tinea capitis/ kerion
Alopecia arreata (no inflammation or scale, hair loss)
Trichotillomania (hairs of different lengths, irregular pattern)

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14
Q

DDx of vesiculobullous rash

A
  • Acquired: Bullous arthropod bites, scabies, drug reaction, friction blisters, burns, dyshidrotic eczema, vasculitis (KD, HSP), frost bite, acropustulosis of infancy
  • Congenital: epidermolysis bulla, incontinetia pigmenti, mastocytosis
  • Autoimmune: linear IgA disease (chronic bullous disease of childhood), bullous pemphoigoid, SLE, dermatitis herpetiform
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15
Q

DDx of blistering rash

A
  • SJS, TEN, SSSS, VZV, disseminated herpes zoster infection (can also see pneumonia, encephalitis, hepatitis), disseminated HSV infection, sweet syndrome, bullous SLE
  • Other generalized blistering disorders: bullous impetigo, bullous pemphigoid, epidermolysis bullosa
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16
Q

List 5 types of drug eruptions

A
  1. Urticaria
  2. “Simple drug reaction” - morbilliform
  3. Drug hypersensitivity reaction/ DRESS
  4. Pustular: AGEP (acute generalized exanthematous pustulosis)
  5. Vesiculobullous - fixed drug eruption, erythema multiforme,. SJS/TEN
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17
Q

Work-up for suspected DRESS

A

Check echo, eosinophilia, renal/ liver function, thyroid function

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18
Q

Causes of erythema multiforme

A
  • infectious triggers – HSV1/2, mycoplasma

- medications – sulfonamides, abx, antiepileptics

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19
Q

Clinical characteristics and treatment of erythema multiforme?

A

target lesions (3 zones), often distal extremities. Bullous lesions can rupture. Mucous membrane involvement (1/2 cases), lesions themselves are fixed. Systemic symptoms of fever, malaise, arthralgias are present. Self-limited, lasts 2-3 weeks, stop any offending meds, can treat HSV with acyclovir, antihistamines

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20
Q

Clinical features of SJS/TEN?

A

SJS < 10%, TEN > 30%
Fever + systemic symptoms – then bullous rash, rupture and desquamation + necrosis.
Nikolsky sign = areas of skin sheer off with gentle pressure.
Involvement of 2+ mucous membranes (oral, ocular, urethral, genital), ocular involvement, scarring. Usually 1-3 weeks after medication.

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21
Q

Treatment of SJS/TEN?

A

Stop offending meds, wound care – petroleum gauze, analgesia, nutrition, watch for infection. Can use IVIG

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22
Q

How to differentiate EM vs. SJS/TEN vs. SSSS

A
  • Classic targets in EM
  • SJS/TEN usually starts on face and trunk, EM on extremities
  • EM can involve mucous membranes, but 2+ involved in SJS/TEN
  • SSSS affects superficial skin (not full thickness), and no oral mucosal involvement
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23
Q

Manifestations of neonatal lupus

A

Annular, red, scaly patches. anti-Ro, anti-La. Skin and cardiac (third degree AV block), hematologic (thrombocytopenia, anemia, neutropenia)

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24
Q

What electrolyte to test in subcutaneous fat necrosis

A

Calcium - hypercalcemia

25
Q

DDx of diaper dermatitis?

A
  • Irritant contact dermatitis (skin folds are spared)
  • Atopic or seborrheic dermatitis
  • Moniliasis (candida) - skin folds involved, beefy red plaques, satellite papules
  • Acrodermatitis enteropathica (zinc deficiency), Langerhans, psoriasis
26
Q

Treatment of diaper dermatitis?

A
  • Frequent diaper changing, air exposure, gentle cleansing.
  • Barrier diaper creams: zinc oxide, petrolatum, silicone.
  • Topical steroids (1% hydrocortisone) if atopic or seborrheic dermatitis component.
  • Topical nystatin or clotrimazole BID if candida (PO nystatin if also have oral thrush)
27
Q

Guttate psoriasis is frequent preceeded by which infection?

A

often preceeded by strep infection

28
Q

List 6 secondary skin lesions

A

crust, scale, fissuring, erosions, ulceration, umbilication, excoriation, atrophy, lichenification, scar

29
Q

Molluscum more common with which physical activities?

A

swimmers and wrestlers

30
Q

Treatment of molluscum?

A

Spontaneously resolve; if treating – apply local EMLA, prick the skin over the core with 26G needle and squeeze core out, or use liquid nitrogen. Can apply 0.1% tretinoin cream or cantharidin if affecting large areas (avoid in face or genital areas as can cause blistering)

31
Q

Treatment of warts?

A

Often recur, disappear with time.

Treatment: airtight occlusion with duct tape for 1 month, salicylic acid, liquid nitrogen.

32
Q

Treatment of brown recluse spider bite?

A

tetanus prophylaxis, dapsone for necrosis (not in G6PD), surgical debridement, antivenom if systemic signs

33
Q

Treatment of scabies?

A

Tx with 5% permethrin cream, x 12 hours (keep overnight), re-treat 1 week later.
Asymptomatic and symptomatic household members should all be treated at the same time.
For infants < 3 months can tx with Sulphur (8%–10%) precipitated in petroleum jelly

34
Q

Treatment of lice?

A

Tx with 1% permethrin or pyrethrin cream x 10 min (repeat 7-10 days later), can also apply Vaseline to hair x 1 week, isopropyl miristate (Resultz) or dimeticone

35
Q

How does pyogenic granuloma present?

A

papule/nodule develops at the site of trauma or burn, bleed easily. Remove

36
Q

What is Darier’s sign?

A

scratch a papule and develop a hive –> contains Mast cells (mastocytoma or urticaria pigmentosa).

37
Q

Triggers for erythema nodosum?

A

Infectious (strep, TB, histoplasmosis), IBD, sarcoidosis, meds (OCP)

38
Q

DDx of morbilliform rash and severe illness?

A

measles (rubeola), KD, RMSF, DRESS, Dengue fever

39
Q

Clinical features of measles?

A

10-14 days incubation period, cough, coryza and conjunctivitis, fever –> Koplik spots –> morbilliform rash (head –> toe).

40
Q

How does scarlet fever present?

A

Group A strep makes erythrogenic toxin. Fine, raised, generalized, morbilliform rash (sandpaper feel), strawberry tongue. Pastia’s lines = bright red lines in axilla, folds.

41
Q

How does pityriasis rosea present?

A

Christmas tree pattern of papules and plaques with “collarette of scale”, herald patch. HHV 6 or 7

42
Q

Triggers of Gianotti-Crosti (papular acrodermatitis)

A

Hep B, EBV (CMV, enterovirus, influenza + many more).

43
Q

Clinical features of rubella?

A

Rash head –> toes over 2-3 days, gone by 4th day. Rash doesn’t coalesce. Fever is uncommon, joint pain and adenopathy.

44
Q

Causes/ DDx of urticaria?

A

Urticaria – acute (< 6 weeks) vs. chronic (> 6 weeks), individual wheels last < 24 hours.
• Idiopathic
• Insect bites
• Allergy to drugs or food
• Infection: Viral (EBV, hepatitis), Bacterial (strep), parasitic
• Cold urticaria
• Dermatographism

45
Q

What is eponychia/ paronychia?

A

Eponychia is superficial cellulitis of cuticle –> forms a pocket of pus and is this called a paronychia

46
Q

Treatment of herpetic whitlow?

A
  • Oral acyclovir given in first few days to shorten course, but does not have to be given (self-limited condition)
  • If immunocompromised IV acyclovir
47
Q

What is a felon? What is the treatment?

A
  • Deep infection into distal pulp space of finger can be caused by punctures or splinters
  • Usually very tender swollen finger tip that is tense, warm and red – “minicompartment syndrome”
  • Can lead to osteomyelitis, tenosynovitis, septic arthritis
  • Treatment is incision, dissections and drainage; digital block for analgesia; extend incision past DIP joint to prevent flexor contracture then oral antibiotics (Keflex x 10 days) and close follow up
48
Q

What is the treatment for a subungual hematoma?

A

Tx = nail trephination if intact nail margins (regardless of size of hematoma).

  • If nail or margins are disrupted +/- displaced phalanx fracture –> remove nail and perform nail bed repair
  • Abx prophylaxis if underlying fracture/ significant soft tissue injury
49
Q

Removal techniques for a hair tourniquet? (list 3)

A
  1. Forceps and thin probe inserted below hair, then cut with scissors
  2. Nair
  3. Remaining hair or very deep –> digital block and perpendicular incision (over the hair) at 3 or 9 o’clock (to avoid neurovascular bundle)
50
Q

How does Sturge Weber present?

A

Port wine stain, ipsilateral vascular angiomatosis of leptomeningies and ocular vessels; seizures/MR/hemiplegia and glaucoma.

51
Q

What are the 3 types of hemangiomas?

A
  • Superficial (red, raised)
  • Deep hemangiomas (bluish hue)
  • Mixed
52
Q

What is Kasabach-Merritt phenomenon?

A

Very large hemangioma can develop Kasabach-Merritt phenomenon (consumptive coagulopathy with hemolytic anemia, CHF, thrombocytopenia)

53
Q

Red flags for hemangiomas?

A
large face hemangioma (PHACES syndrome)
Midline prevertebral
airway, eye and nose involvement 
beard distribution and laryngeal hemangioma --> stridor
large liver hemangioma at risk CHF
54
Q

Treatment of umbilical granuloma?

A

cauterization with silver nitrate (cover the surrounding skin with gauze to prevent burn)

55
Q

DDx of umbilical granuloma?

A

omphalomesenteric duct or patent urachus

56
Q

Risk factors for pilonidal sinuses/ cysts?

A

Obesity, hirsutism and sedentary lifestyle

57
Q

Tx of urethral prolapse

A

treatment of predisposing condition, pain control, topical antibiotic cream and twice daily estrogen cream

58
Q

Rectal prolapse risk factors

A

severe constipation or severe diarrhea; also think spina bifida, CF, pinwords, sigmoid intussuception

59
Q

Blistering rash on hand of teen after canoe trip. List 6 possible etiologies

A
  • poison ivy, poison oak, poison sumak
  • bullous impetigo
  • polymorphous light eruption
  • swimmer’s itch
  • bug bites with local reaction
  • vibrio vulnificus