Miscellaneous Lesions Flashcards
(35 cards)
Angioedema description and forms
- deeper swelling of the skin involving subcutaneous tissues; often involves the eyes, lips, and tongue
- may or may not accompany urticaria
- hereditary or acquired forms
Hereditary angioedema description, onset and triggers
• hereditary angioedema (does not occur with urticaria)
■ onset in childhood; 80% have positive family history
■ recurrent attacks; 25% die from laryngeal edema
■ triggers minor trauma, emotional upset, temperature changes
Types of acquired angioedema
■ acute allergic angioedema (allergens include food, drugs, contrast media, insect venom, latex)
■ non-allergic drug reaction (drugs include ACEI)
■ acquired C1 inhibitor deficiency
Angioedema treatment
■ prophylaxis with danazol or stanozolol for hereditary angioedema
■ epinephrine pen to temporize until patient reaches hospital in acute attack
Urticaria description and pathophysiology
- also known as “hives”
- transient, red, pruritic well-demarcated wheals
- each individual lesion lasts less than 24 h
- second most common type of drug reaction
- results from release of histamine from mast cells in dermis
- can also result after physical contact with allergen
DDx for urticaria
DAM HIVES
Drugs and foods
Allergic
Malignancy
Hereditary Infection Vasculitis Emotions Stings
Acute urticaria
> 2/3 of cases
Attacks last <6 wk
Individual lesions last <24 h
Acute urticaria etiology
Drugs; especially ASA, NSAIDs
Foods: nuts, shellfish, eggs, fruit
Idiopathic (vast majority)
Infection
Insect stings (bees, wasps, hornets)
Percutaneous absorption: cosmetics, work exposures
Stress
Systemic diseases: SLE, endocrinopathy, neoplasm
Chronic urticaria
<1/3 of cases
Attacks last >6 wk
Individual lesion lasts <24 h
Chronic urticaria etiology
IgE-dependent: trigger associated
- Idiopathic (90% of chronic urticaria patients)
- Aeroallergens
- Drugs (antibiotics, hormones, local anesthetics)
- Foods and additives
- Insect stings
- Parasitic infections
- Physical contact (animal saliva, plant resins, latex, metals, lotions, soap)
Direct mast cell release
- Opiates, muscle relaxants, radio-contrast agents
Complement-mediated
- Serum sickness, transfusion reactions
- Infections, viral/bacterial (>80% of urticaria in pediatric patients)
- Urticarial vasculitis
Arachidonic acid metabolism
- ASA, NSAIDs
Physical
- Dermatographism (friction, rubbing skin), cold (ice cube, cold water), cholinergic (hot shower, exercise), solar, pressure (shoulder strap, buttocks), aquagenic (exposure to water) adrenergic (stress), heat
Other
- Mastocytosis, urticaria pigmentosa
Approach to urticaria
- Thorough Hx and P/E
- Acute: no immediate investigations needed; consider referral for allergy testing
- Chronic: further investigations required: CBC and differential, urinalysis, ESR, TSH, LFTs to help identify underlying cause
- Vasculitic: biopsy of lesion and referral to dermatology
Wheal
- Typically erythematous flat-topped, palpable lesions varying in size with circumscribed dermal edema
- Individual lesion lasts <24 h
- Associated with mast cell release of histamine
- May be pruritic
Mastocytosis (Urticaria Pigmentosa)
Rare disease due to excessive infiltration of the skin by mast cells. It manifests as many reddish-brown elevated plaques and macules. Friction to a lesion produces a wheal surrounded by intense erythema (Darier’s sign), due to mast cell degranulation; this occurs within minutes
Urticarial vasculitis description and intervention
Individual lesions last >24 h
Often painful, less likely pruritic, heals with bruise type lesions
Requires biopsy
Urticarial vasculitis etiology
Idiopathic Infections Hepatitis Autoimmune diseases SLE Drug hypersensitivity Cimetidine and diltiazem
Erythema nodosum clinical presentation
- acute or chronic inflammation of subcutaneous fat (panniculitis)
- round, red, tender, poorly demarcated nodules sites: asymmetrically arranged on extensor lower legs (typically shins), knees, arms
- associated with arthralgia, fever, malaise
Erythema nodosum etiology
- 40% are idiopathic
- drugs: sulfonamides, OCPs (also pregnancy), analgesics, trans retinoic acid
- infections: GAS, TB, histoplasmosis, Yersinia
- inflammation: sarcoidosis, Crohn’s > UC
- malignancy: acute leukemia, Hodgkin’s lymphoma
Erythema nodosum epidemiology
- 15-30 yr old, F:M = 3:1
* lesions last for days and spontaneously resolve in 6 wk
Erythema nodosum investigations
- chest x-ray (to rule out chest infection and sarcoidosis)
* throat culture, ASO titre, PPD skin test
Erythema nodosum management
- symptomatic: bed rest, compressive bandages, wet dressings
- NSAIDs, intralesional steroids
- treat underlying cause
DDx of Erythema Nodosum
NODOSUMM NO cause (idiopathic) in 40% Drugs (sulfonamides, OCP, etc.) Other infections (GAS+) Sarcoidosis UC and Crohn’s Malignancy (leukemia, Hodgkin’s lymphoma) Many Inections
Pruritus ddx
SCRATCHED Scabies Cholestasis Renal Autoimmune Tumours Crazies (psychiatric) Hematology (polycythemia, lymphoma) Endocrine (thyroid, parathyroid, Fe) Drugs, Dry skin
• dermatologic – generalized
■ asteatotic dermatitis (“winter itch” due to dry skin)
■ pruritus of senescent skin (may not have dry skin, any time of year)
■ infestations: scabies, lice
■ drug eruptions: ASA, antidepressants, opiates
■ psychogenic states
• dermatologic – local ■ atopic and contact dermatitis, lichen planus, urticaria, insect bites, dermatitis herpetiformis ■ infection: varicella, candidiasis ■ lichen simplex chronicus ■ prurigo nodularis
• systemic disease – usually generalized
■ hepatic: obstructive biliary disease, cholestatic liver disease of pregnancy
■ renal: chronic renal failure, uremia secondary to hemodialysis
■ hematologic: Hodgkin’s lymphoma, multiple myeloma, leukemia, polycythemia vera, hemochromatosis, Fe deficiency anemia, cutaneous T-cell lymphoma
■ neoplastic: lung, breast, gastric (internal solid tumours), non-Hodgkin’s lymphoma
■ endocrine: carcinoid, DM, hypothyroid/thyrotoxicosis
■ infectious: HIV, trichinosis, echinococcosis, hepatitis C
■ psychiatric: depression, psychosis
■ neurologic: post-herpetic neuralgia, multiple sclerosis
Pruritus investigations
CBC, ESR, Cr/BUN, LFT, TSH, fasting blood sugar, stool culture and serology for parasites
Pruritus management
- treat underlying cause
- cool water compresses to relieve pruritus
- bath oil and emollient ointment (especially if xerosis is present)
- topical corticosteroid and antipruritics (e.g. menthol, camphor, phenol, mirtazapine, capsaicin)
- systemic antihistamines: H1 blockers are most effective, most useful for urticaria
- phototherapy with UVB or PUVA
- doxepin, amitriptyline
- immunosuppressive agents if severe: steroids and steroid-sparing
