Dermatology Flashcards by Bryn Longcroft-Harris

Mastocytosis

Caused by abnormal proliferation of mast cells
Urticaria pigmentosa is the mot common form
Typically before 1 year of age
Appearance: Orangish-brown macules, plaques, or nodules, usually on trunk, form a wheal with stroking (Darier sign)
Self resolves

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Mastocytosis treatment

Avoid triggers (heat, touching, NSAIDs, ASA, opioids)
H1 antihistamines
Topical steroids for urtication or blistering
EpiPen if risk of anaphylaxis
Cromolyn sodium or ketotifen (mast cell stabilizing agent) for GI symptoms or some systemic symptoms like headache

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4 modes of pathogenesis for acne

Alteration in the keratinization process
Sebum production by the sebaceous gland
P. acnes follicular colonization
Release of inflammatory mediators in to the skin

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Common SJS/TEN triggers

Drugs (sulfonamides, anti-seizure medications, NSAIDs)
Infections (HSV, EBV, mycoplasma, HBV)

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SJS vs TEN

< 10% of epidermis involved = SJS, typically painless or minimal
> 30% involvement = TEN, typically painful

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SSSS vs SJS/TEN

Split in the skin is much more superficial (subcorneal) in SSSS compared to TEN (full-thickness)
No perioral crusting in SJS/TEN

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Dermatitis herpetiformis

IgA antibodies are directed at epidermal transglutaminase
All patients with dermatitis herpetiformis have celiac disease!
Symmetric, grouped, small, tense, red, stinging, ++ itchy papules and vesicles, pleomorphic
Mucous membranes usually spared, can see on knees, elbows, shoulders, buttocks, head
Respond within weeks to months of a gluten free diet
Can cautiously give dapsone for itching

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Drugs that cause photosensitivity

Antibiotics (sulfonamides, tetracyclines, fluroquinolones)
NSAIDs
Retinoids
Thiazides
Antifungals

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How does BPO work

Decreases antibacterial resistance in p. acne

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Birth control for accutane

2 effective BC for 1 month before, during, and 1 month after use
2 neg preg tests before starting, monthly tests during preg

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What is the neuro concern for a child with giant cell pigmented nevus?

Leptomeningeal melanocytosis
Can cause seizures, hydrocephalus, increased ICP, ID, and motor deficits

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Appearance of
1. Junctional
2. Compound
3. Dermal
cutaneous nevi

Brown, flat, junction of dermis and epidermis
Tan to brown, minimal/moderate elevation, within dermis or dermal-epidermal junction
Pink, elevated, dome shaped, within dermis

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New ABCDE for pediatric melanoma

A: Amelanotic
B: Bleeding/bumps
C: Colour uniform
D: Diameter small/de novo
E: Evolution

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Tinea versicolour
1. Appearance
2. Diagnosis
3. Treatment

Trunk, neck, arms. Reddish brown in white people, hypo or hyperpigmented in darker skin, fine scale, little to no itch
Fungal infection, yellow under Wood’s lamp
Antifungal shampoo or cream, can try PO

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Pityriasis alba
1. Appearance
2. Treatment

Hypopigmented, ill defined, round or oval patches with fine scale, more noticeable in the sun
Moisturizer, avoid sun, low potency steroid or CI if itchy, red, or scaly

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Vitiligo
1. Appearance
2. Treatment

White macules and patches (DEpigmentation), margins can be hyperpigmented
Potent topical steroid, UVB if more extensive, sun protection
Most people will at least check thyroid function

Accutane side effects and screening

Dry lips, skin, mouth, sun sensitivity, back and joint pain
Hypertriglyceridemia, increased LFTs - get triglyc, chol, and LFTs before starting, then 4 and 8 weeks after

Erisipelas

Bright pink, well demarcated plaques
Superificial infection from spread through dermal lymphatics
Better defined borders and develops faster than cellulitis
Treat with antibiotics

Natural history and timeline of infantile hemangiomas

Not present at birth
Show up in first 1-2 weeks of life, no later than 3 mo
Proliferative phase for first 6 mo
Plateau 6-12 mo
Involute around 1 year old

Which hemagiomas need further work up?

5+ cutaneous - abdo US for liver hemangiomas
Segmental beard area - risk of airway
Large segmental facial lesions - ?PHACES
Lumbosacral/perineal segmental lesions - ?LUMBAR syndrome

Congenital hemangiomas

Present at birth
May or may not involute
Cannot treat with beta blockers

Pityriasis rosacea rash and treatment

Adolescents, trunk, may have viral prodrome (HHV 6 or 7)
Often first presents with Herald patch (annular, central clearing)
Well demarcated generalized erythematous plaques/papules with collarette of scale
Resolves by 3 mo, can treat itch

Nail changes in psoriasis

Oil drop sign
Pitting
Nail fragility
Onycholysis

Treatment for
1. Mild to moderate
2. Moderate to severe
psoriasis

Topical steroids, CIs, vit D analogues, emollients
TNF inhibitors, phototherapy, MTX

Yearly screening for patients with psoriasis

Weight check BP Mood Arthritis Uveitis (if psoriatic arthritis)

Acne classification

Mild = mainly comedones, < 10 papules/pustules Moderate = 10-40 papules/pustules, may have back/trunk lesions Moderate-severe = 40-100 papules/pustules, up to 5 nodules, widespread affected areas Severe = nodulocystic, multiple large painful nodules

Treatment for mild comedonal acne

Topical retinoid Alt. topical salicyclate or azelaic acid

Treatment for mixed papular/pustular acne

Topical retinoid +/- BPO, topical antibiotic (erythromycin, clindamycin) Use topical abx with BPO to prevent resistance Can use combo products

When to add PO abx for acne

Moderate to severe inflammatory papulopustular and nodulocystic acne Anti-inflammatory and antibacterial properties Use with topical retinoids and BPO, not topical abx Ex: minocycline, doxycycline > tetracycline

When to use OCP for acne

Acne and hormonal abnormalities Acne unresponsive to antibiotic therapy, not candidates for isotretinoin

Alopecia areata

Sudden, oval, well demarcated patches of COMPLETE alopecia No rashes or scarring Surrounding exclamation point hairs Tx: potent topical steroids, injection steroids, cosmetic coverings

Erythema toxicum

Lesions are firm, yellow white, 1-2 mm papules or pustules with surrounding erythematous flare Peak incidence on second day of life – waxes and wanes over first few days (lasts 3-7 days)

Neonatal pustular melanosis

Transient, benign, self limiting condition 3 types of lesions: evanescent superficial pustules, ruptured pustules with fine scale +/- central hyperpigmented macule, and hyperpigmented macules Present at birth! Pustules last 2-3 days, hyperpigmented macules can last up to 3 months

Miliaria

Results from retention of sweat occluded in eccrine sweat ducts Asymptomatic, noninflammatory, pinpoint, clear vesicles From overheating

What age group always needs a work up if presenting with acne?

Mid-childhood acne (ages 1-7 years) Consider precocious puberty, late onset CAH, or androgen secreting tumors

Sucking blister

Solitary or scattered superficial bullae Present at birth on upper limbs Presumably induced by vigorous sucking in uteror Radial aspect of forearm, thumb, and index finger Resolves without treatment May see sucking pads (calluses) on the lips

Tinea capitis 1. Rash presentation 2. Diagnosis 3. Treatment

1. Partial alopecia with scale, often occipital lymphadenopathy 2. Fluoresce under Wood's lamp, take fungal scraping for KOH and culture before treatment 3. SYSTEMIC antifungals! Oral terbinafine x 4-6 weeks, also griseofulvin for 6-8 weeks, treat with antifungal shampoo to reduce risk of spread of infection to other household members, systemic steroids if kerion present

Scabies treatment

5% permethrin 8-14 hours, repeat 7 days later Infants: scalp and face to toes Children: neck to toes Prophylactic therapy for household members regardless of symptoms