Inflammatory Lesions Flashcards by Jordan Trager

What is ichthyosis?

(appearance and histologic features)

impaired epidermal maturation

hyperkeratosis
dry, coarse “fish-like” scales

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Where and in what populations is ichthyosis most commonly seen?

-extensor surfaces

Inherited: first year of life, usually resolving around adolescence

Aquired: as a paraneoplastic syndrome

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What is urticaria?

(appearance and histologic features)

hives/wheals

transient, pruitic, edmatous papules/plaques
angioedema: swelling of dermis and subcutaneous fat
dermal edema
epidermis unchanged

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What are the mechanisms of urticaria?

Mast cell degranulation:

IgE dependent; type I hypersensitivities/allergies/anaphylaxis
IgE independent; substances that stimulate degranulation directly

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What is acute eczematous dermatitis?

(appearance and histologic features)

red papular/vesicular, oozing, crusted lesions
scaling plaques if persistent

Acute lesions

spongiosis (edema of the epidermis)
acantholysis (seperation of keratinocyte -> vesicle formation)

Persistent lesions

acanthosis (diffuse epidermal hyperplasia)
hyperkeratosis

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What is the mechanism of acute eczematous dermatitis?

Type IV hypersensitivity

-requires sensitization

-delayed reaction following stimulus

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What is erythema multiforme?

(appearance and histologic features)

self-limited T-cell mediated, hypersensitivity

various lesions types (hence multiforme), classically erythematous macule -> papule -> targetoid lesion
infiltrating lymphocytes
areas of epidermal necrosis

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Where and in what populations is erythema multiforme most commonly seen?

typically start on hands/feet and extend proximally
young/middle aged adults (20-40 years)

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What are common causes of erythema multiforme?

Infection

herpes simpex
mycoplasma
histoplasmosis
coccidiodomycosis
typhoid

Drugs:

penicillins
sulfonamides
antimalarials

Certain cancers

Autoimmune diseases

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What is Stevens-Johnson syndrome?

Complication of erythema multiforme

targetoid lesions of erythema multiforme
fever*** (differentiating feature)
involvement of <10% surface area
involvement of mucous membranes
sloughing of skin -> fluid loss -> shock

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What is toxic epidermal necrolyis (TEN)?

Severe form of Stevens-Johnson syndrome

fever
targetoid lesions of erythema multiforme
involvement of >30% surface area*** (differentiating feature)
involvement of mucous membranes
sloughing of skin -> fluid loss -> shock

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What is psoriasis?

(appearance and histologic features)

Chronic inflammatory dermatosis

associated with mild to severly deforming arthritis
pink to salmon-colored plaque with adherent silver-white scale
pruritic
nail involvement (pitting or separation/onycholysis)
acanthosis (epidermal hyperplasia)
elognated rete ridges
Munro microabscesses (neutrophils in stratum conreum)
parakaratosis

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Where and in what populations is psoriasis most commonly seen?

extensor surfaces
young/middle aged adults (20-40 years)

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What are characteristic/diagnositic features of psoriasis?

Koebner phenomenon:

physical stimuli (scratching, irritation, or trauma) produces lesion
lesions are pruritic which can cause propagation of lesions

Auspitz sign:

-removal of scale results in pinpoint bleeding

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What is the treatment for psoriasis?

-corticosteroids

PUVA

-Psoralen with UVA

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What is seborrheic dermatitis?

(appearance and histologic features)

Chronic inflammatory dermatosis

dandruff is a form
erythematous papules on erythematous base with scales and greasy yellow crusts

-parakaratotic mounds

-follicular lipping

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Where and in what populations is seborrheic dermatitis most commonly seen?

Oily skin (numerous sebaceous glands)

forehead, around the ears, nasolabial fold, presternal
more common in men (androgens?)
bimodal; infants and puberty

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What conditions are associated with development of seborrheic dermatitis?

Malassezia colonization
adrongens (increased sebum)
Parkinson’s disease
HIV w/ low CD4 count

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What is lichen planus?

(appearance and histologic features)

Chronic inflammatory dermatosis

six “P’s”

pruritic
purple
polygonal
planar (flat top)
papules
plaques

Wickham striae: white lines on surface of lesion

hyperkeratosis
hypergranulosis (-> Wickham striae)
saw-tooth acanthosis
band-like lymphocyte infiltrate of dermal-epidermal junction

Where is lichen planus most commonly seen?

Symmetrically on extremities

-wrists, elbows, and ankles

Mucosa

What condition is associated with development of lichen planus?

chronic hepatitis C infections

What cancer is associated with lichen planus?

squamous cell carcinoma of chronically infected mucosa

What is pemphigus?

(mechanism, appearance, and histologic/immunofluorescence features)

Blistering disease

IgG autoantibodies against desmogleins (in desmosomes)
vesicles/bullae -> rupture to form erosions and crusts
non-pruritic
acantholysis (above the basal layer)
“tombstone” appearance; basal layer attached to basement membrane
fishnet-like immunofluorescence surrounding keratinocytes

Where and in what populations is pemphigus most commonly seen?

older adults (40-60)
first appear in oral mucosa, later in intertriginous areas

What is a characteristic clinical finding of pemphigus that helps to differentiate it from other blister disorders?

**Nikolsky's sign**: -**thin vesicle/bullae** (they are intraepidermal and more superficial) **readily rupture** -\> **erosions and crusts**

What is **bullous pemphigoid**? (**mechanism**, appearance, and histologic/**immunofluorescence** features)

Blistering disease - **IgG autoantibodies** against **BPAg** (in **hemidesmosomes**) - **tense bullae, don't rupture** - pruritic **-subepidermal, nonakantholytic** -**linear** immunofluorescence **along basement membrane**

**Where** and in **what populations** is **bullous pemphigoid** most commonly seen?

- **inner thigh, flexor surfaces, axilla, groin** - RARE mucosal involvement - **elderly** (over 60)

What is **dermatitis herpetiformis**? (**mechanism**, appearance, and histologic/**immunofluorescence** features)

Blistering disease - **IgA autoantibodies** against **gluten analog in epidermal basement membrane** - **tense,** **grouped vesicles** (herpetiform) - **extremely pruritic** - **subepidermal** blister at **tip of dermal papillae** **-noncontinuous** immunofluorescence at **tip of dermal papillae**

**Where** and in **what populations** is **dermatitis herpetiformis** most commonly seen?

- **extensor surfaces** - NO mucosal involvement - **middle aged** adult **males** (30-40)

What **condition** is **associated** with development of **dermatitis herpetiformis**?

**celiac disease**, autoantibody is against gluten like substance in basement membrane

What is the **treatment** for **dermatitis herpetiformis**?

gluten free diet

What is **epidermolysis bullosa**? (**mechanism** and **onset)**

Non-inflammatory, **inherited** blistering disease - **blisters easily form** from **mechanical stress** - **onset at birth**

What are **porphyrias** and how do they relate to the skin? (**mechanism**)

**Inherited** defects in porphyrin synthesis - **deposition of intermediates into skin** can occur -\> fragile skin -\> **_blisters_** - **subepidermal** vesicles, scar when ruptured - **worsens with sun exposure**

What is **acne vulgaris**? | (appearance and histologic features)

- **erythematous** **papules, nodules, or pustules** - may have open or closed comedones, **white/black heads** (**keratin plug** either visible or below epidermal surface)

What are causes of **acne vulgaris**?

- keratinization of follicle -\> **keratin plug** - hypertrophy of sebaceous glands (**androgens in puberty**) - ***Propionibacterium acnes*** colonization of follicle

What is the **treatment** for **acne vulgaris**?

- benzoyl peroxide (antimicrobial)/antibiotics - vitamin A derivatives

What is **rosacea**? | (appearance and histologic features)

- **facial flushing** - persistent **erythema w/ telangiectasia** - pustules/papules - **rhinophyma** (**thickend nasal skin** by papules)

What is the **mechanism** of **rosacea**?

-increased levels of **cathelicidin** (antimicrobial peptides)

**Where** and in **what populations** is **rosacea** most commonly seen?

- **face**, particularly around the **_nose_** - more common in **women** - **mid-older adults** (30-60)

What is **paniculitis**?

inflammation of **subcutaneous adipose**

What is **erythema nodosum**? | (appearance and histologic features)

Panniculitis (subcutaneous adipose inflammation) - **firm, tender, erythematous nodules** - more noticeable by palpation than inspection - subcutaneous edema and infiltration

What is **erythema induratum**? | (appearance and histologic features)

Panniculitis (subcutaneous adipose inflammation) - **tender, erythematous nodules** - **ulcerate** - **subcutaneous granulomas/necrosis**

What are **verrucae**? | (appearance and histologic features)

**Warts** (**HPV** infection) - **skin colored papules** - epidermal **hyperkeratosis/hyperplasia**

What is **molluscum contagiosum**? | (appearance and histologic features)

caused by **Pox** virus - **skin colored** papule with **umbilication** - **Molluscum bodies**

What is **impetigo**? | (appearance and histologic features)

***Staphylococcus aureus (bullous)*** or **Strep A (non-bullous)** infection of the skin - erythematous macules -\> pustules - **honey-colored crust** - neutrophil infiltration under stratum corneum -\> pustules