Dermatology - Acute Inflammatory Flashcards
What is defined by a pruritic rash consisting of transient raised erythmetous wheals that persists for less than 24 hours? It involves edema of the dermis.
Urticaria
What is Urticaria mediated by after exposure to allergen?
Immune response - IgE and histamine Eosinophils and lymph
What is defined by painful (less pruritic) intense edema of the dermis and epidermis, especially the eyes, lips, palms, groin? If it is laryngeal it can become emergent.
Angiodedema
Name some the type 1 IgE mediated allergens for Urticaria.
Food: Latex: Stinging insects: Medications: Aeroallergens:
Shellfish, fish, peanuts, tree nuts, eggs, milk, soy, wheat
Latex
Bees, wasps, hornets, fire ants, bedbugs, fleas, mites
Medications: sulfa, penicillins, cephalosporins
Aeroallergens: dust mites, pollen, molds, animal dander
Explain the immediate hypersensitivity reaction
First Exposure: Production of IgE by B cell in response to T cell cytokine release. IgE binds to FcE receptor on mast cells or basophils.
Next Exposure: Antigen exposure and crossing linking of bound IgE, Mast cell activation and release of mediators (histamine, leukotrienes, cytokines, chemotatci functions, enzymes)
Name the autoimmune causes of immune Urticaria
Autoimmune diseases - Hashimotos immune thyroiditis (antithyroid antibodies), SLE, vasculitis
What are the infections causes of immune Urticaria?
Viral - Cytomegalo virus, Epstein-Barr, HIV, Hep A, B, C
Parastitic, Fungal, or bacterial
What are some physical Urticaria stimulations?
Solar Cholinergic (Sweating vs Heat) Cold Dermographism (friction, can write on skin) Water Vibratory Pressure (burning hands, feet, or butt)
Smal papules on red skin that occur on the back of the neck within 30 minutes of exercise…
Cholinergic Urticaria
Erythmetous area of skin that persists due to a cold object being held on it…
Cold Urticaria
Positive Ice Cube Test
Erythmetous lines that persists after ‘drawing’ on ones arm with blunt object
Dermophraphic Urticaria
What are causes of direct mast cell degranulation in non-immune urticaria?
Narcotics - Codein and Morphine Sulfate Aspirin NSAIDs Radiocontrast Media Dextran Ace inhibitors angioderma Vancomycin - Red Man Syndrome
What are histamine containing foods that cause a non-immune Urticaria?
Strawberries Tomatoes Shrimp Lobster Cheese Spinach Eggplant
What is defined by erythematous iris-shaped papular and veisculobullous lesions that involves the extremities (palms and soles) and mucous membranes? Half of cases are in pts under 20 years old and more common in males.
Erthema Multiforme
Can differentiate from hives because it does not itch and it is fixed!
What are the causes of Erthema Multiforme?
Sulfonamides (bactrim), phenytoin, barbiturates, phenylbutazone, penicillin, allopurinol
Infection of Herpes Simplex Virus, Mycoplasma
More than 50% of cases are idiopathic
Erthema Multiforme Minor VS Major
Minor involves less than 1 mucosal site, usually caused by a post herpes simplex infection with onset of EM rash at day 10
Major EM is usually caused by a drug reaction, Severe with extensive mucous membrane involvement - Steven Johnson Syndrome. Or occurs after a mycoplasma pneumonia reaction
What is the key feature of Steven Johnson Syndrome?
Toxic Epidermal Necrolysis
Extensive mucosal and epidermal necrosis and sloughing
It occurs 1-3 weeks post initial drug exposure
Life threatening - pts treated in burn unit - Total body 2nd degree burn
What are risk factors for SJS?
Systemic Lupus Erythematosis
HLA-B12
HIV
What is defined by a fixed hyper pigmented or erythmetous macule/patch that can itch, burn, or be asymptomatic? Usually is predisposed to face and genitals.
Fixed Drug Eruption
Usually reoccurs in same area if exposed to drug again. Mechanism is unknown. Hyperpigmentation may be permanent.
What is defined by erythmetous tender nudules that typically occur on the anterior aspect of shins and in young women?
Panniculitis Erythema Nodosom
What are the causes of Panniculitis Erythema Nodosom?
Strep, TB, Fungal Infection
Meds - Oral Contraceptives, Sulfa, NSAIDs
Autoimmune - IBD, Sarcoid
What is defined by tender erythmetous nodules occurring in middle aged females on the posterior legs? They may turn into plaques with ulceration.
Panniculitis Erythema Induratum
What is Panniculitis?
A focus of inflammation in subcutaneous tissue. Usually an erythmatous nodule in SQ fat, either septal or lobular depending on where the disease process begins. Can be diagnosed with skin biopsy
