Eczemas and Allergic Skin Diseases Flashcards
What are the characteristics of Pityriasis Alba?
Mild form of Atopic Dermatitis Commonly presents as hypopigmented macules on the face and neck.
What is a simple drug eruption?
ACDR that is limited to the exanthem (skin) only.
What findings would indicate Chronic Urticaria?
If the individual lesions resolve within 24-48 hours, but the reaction continues for >6 weeks. Also, there are no confounding symptoms such as arthralgias or fever.
What is a complex drug eruption?
ACDR that has constitutional symptoms (multi system)
Describe Steven-Johnsons Syndrome and Toxic Epidermal Necrolysis.
They are the same condition, TEN is more severe. Acute, life-threatening reactions to drugs (occasionally idiopathic) Result in extensive necrosis and detachment of the epidermis.
Describe Anaphylaxis.
A severe allergic reaction with life-threatening systemic findings, mainly laryngospasm, airway obstruction, vascular collapse, and hypotension. Usually occurs within 1 hour of exposure.
What medications can be used for atopic dermatitis?
Antihistamines - for itching Skin hydration - emollients and limited use of soap Topical calcineurin inhibitors - for itching, not for use on children
How should emergency department care begin for a patient with anaphylaxis?
O2 2 large-bore IVs for hypotension IV antihistamines IV steroids
What type of reaction is an ACDR?
Most are hypersensitivity, immunologic reactions, varying widely between Type I, II, III, and IV
What precautions should patients at risk for anaphylaxis take?
Carrying an epinephrine auto-injector
How do you diagnose ICD?
Through the history and clinical exam
How may SJS or TEN present?
Begin as target-like lesions or diffuse erythema. Progress to necrosis and epidermal detachment.
What is the Nikolsky sign/phenomenon?
Where the epidermis is dislodged from the dermis when rubbed laterally with your hand. May be seen in EM Major.
What findings would indicate Acute Urticaria?
If the individual lesions resolve within 24-48 hours and the overall reaction resolves in
How do you manage Acute Urticaria?
Remove triggers Antihistamines - H1 blockers for skin and vasculature, reducing pain, itching, and edema H2 blockers - parietal cells (stomach) Corticosteroids (prednisone) - short oral course
How do you manage Chronic Urticaria?
Remove triggers. Refer all cases that are not Acute or Physical. Antihistamines - H1 blockers for skin and vasculature, reducing pain, itching, and edema H2 blockers - parietal cells (stomach)
What findings would indicate Physical Urticaria?
If the individual lesions AND the overall reaction resolves within 2 hours (such as sweat, cold, solar…)
What are symptoms of chronic ICD?
painful burning and itching USUALLY evolves through several stages: chapping, hyperkeratosis with scaling, fissures, and crusting
Where does atopic dermatitis commonly manifest on the body?
Commonly found on the face and flexor surfaces, neck, dorsa of feet and hands
What age group is commonly affected by Pityriasis Alba?
preadolescents
What type of hypersensitivity response can you generally use antihistamines with to treat symptoms?
Type I Immediate - usually involves release of histamines
What are the symptoms of atopic dermatitis?
Pruritic (itchy), excoriated inflammation of the skin Poorly defined erythematous patches, papules, and plaques that may result in a puffy appearance. Linear or punctate erosions develop from scratching. Infants, scaling and wet crusts are common.
What is hypersensitivity?
a local or generalized reaction following contact with a specific allergen to which previous exposure and sensitization has occurred.
Describe Lichen Simplex Chronicus.
Manifests as a chronic patch of lichenification that forms from repetitive rubbing or scratching. This patch has a hypersensitive itch response, which creates a habit of rubbing or scratching that continues its cycle.
Which form of ICD is the most common, acute or chronic?
Chronic. Frequently seen on hands of people exposed to wet work
How do you manage ACD?
Burow’s solution Topical glucocorticoids (ointments preferred over creams) Prednisone - severe cases Oral soporific antihistamines - may help patient sleep
Describe Erythema Multiforme
A cutaneous reaction to antigenic stimuli (autoimmune). May present as a drug reaction or bacterial organism, but MOST COMMONLY a reaction to herpes simplex virus.
What is a Type I Immediate hypersensitivity response?
IgE mediated (antibody) reaction that occurs within minutes of exposure.
What are examples of common irritants/toxic agents?
soaps, detergents, cement, petroleum, acetone, fiberglass, wool, friction, pressure
Describe Urticaria.
A pruritic skin eruption characterized by transient, blanchable wheals of varying shapes and sizes that may become confluent. Usually resolves in 48 hours
Do irritants cause hypersensitivity reactions?
No.
What test might you use to test for a Type I response?
Prick test, testing for IgE
What age group is most commonly affected by atopic dermatitis?
Often begins in infancy and generally resolves in later teenage years
What is a Type IV Delayed hypersensitivity response?
a cell-mediated (T cell) response, usually occurs 48-72 hours of exposure
What are some examples of Type IV Delayed hypersensitivity responses?
Tuberculin skin test Contact Dermatitis
Describe Dyshidrosis (Dyshidrotic Eczematous Dermatitis, DED)
A type of visicular eczema, commonly found on the dorsum of the hand, possibly on the palms of hands and on feet. Recurrent attacks with spontaneous remissions.
What are common allergens that cause ACD?
nickel metal, cosmetic ingredients (fragrances), preservatives, rubber, latex, dyes, plants (poison ivy)
Describe Atopic Dermatitis.
A complex disease that involved genetics, immunology (hypersensitivity), environment (exposure), and skin health. Flare-ups are commonly caused by environmental or irritating agents.
Do irritant reactions stay limited to the site of exposure, or spread beyond the exposed sites?
Limited to area of exposure
What test might you use for a Type IV response?
Patch test, testing for delayed response
How do you diagnose ACD?
through history and physical exam. biopsies may help confirm confusing cases patch tests can help identify offending agents
What is the treatment of Nummular Eczema?
Moisturizers and TOPICAL STEROIDS.
How is the severity of SJS or TEN determined?
Scoring system based on age, heart rate, presence or absence of malignancy, percent of body surface involved, blood tests
What are some examples of Type I Immediate hypersensitivity reactions?
Urticaria, Anaphylaxis
What are the most common cause of simple drug eruptions?
Antibiotics
What is the treatment for Pityriasis Alba?
avoiding triggers topical steroids reassurance that the condition is self limiting
What lab findings may you find with complex drug eruptions?
eosinophilia abnormal liver or kidney function
What factors may exacerbate Dyshidrosis?
Friction, cold, excessive exposure to water. Considered endogenous (not from an allergen or irritant.
Why must you consider the development of a rash while taking a medication to be an ACDR?
ACDRs can mimic ANY inflammatory skin condition.
What are some common causes of urticaria and angioedema?
Drugs, Insects, Parasitic infections, Foods, Preservatives, Latex, Aeroallergens, Dermographism from scratching, cold exposure and rewarming, solar exposure, sweat or increase in body temperature, pressure, hereditary (triggered by trauma)
Under what conditions would a patient experience Allergic Contact Dermatitis (ACD)?
Re-exposure to a substance that the person has become sensitized to.
How do you manage atopic dermatitis?
Be aware of secondary bacterial infections (S. aureus) and viral infections (herpes simplex). Prevent rubbing and scratching - use moisturizers to maintain skin health and prevent dryness. Can use RAST or prick test to identify causative agent.
What type of pathology can you see in acute ICD?
damage to keratinocytes (single exposure)
What are ways to manage ICD?
Prevention - gloves Removal of irritant Burow’s solution Oral glucocorticoids - severe acute cases Topical glucocorticoids - chronic cases (steroids should be started off in a high dose and tapered off)
How is a patient with SJS or TEN treated?
Discontinue Drug! Hospitalize and treat similar to a burn patient - fluids, electrolytes, pain management Avoid debridement Treat complicating infections PREVENT recurrence - medical alert bracelet.
What blood test can identify Hereditary Angioedema?
C’1 Esterase Inhibitor test (C’1 INH) Decreased values indicate a production flaw in the glycoproteins necessary for the body’s complement system to function.
Repeated rubbing of atopic dermatitis lesions may cause what results?
lichenification fissures alopecia
What can cause Eczema?
Irritants or Allergens
What are the symptoms of acute ICD?
painful sensation of burning OR may evolve through stages of Blistering, erosion, crusting, scaling, necrosis, shedding, ulceration, and healing
What are the most common cause of complex drug eruptions?
Sulfonamides Allopurinol Anticonvulsants
Describe Nummular Eczema
Type of eczema with a characteristic coin shape. Commonly distributed on forearms and calves. Unknown Etiology
What may trigger Pityriasis Alba?
sun exposure frequent bathing heat
What age group is primarily affected by Lichen Simplex Chronicus?
Mainly occurs in adults, who often have a history of Atopic Dermatitis.
What might cause Acute Urticaria?
Drug or food reaction. Possibly a parasitic infection.
What is Allergic Phytodermatits?
ACD due to plants - Poison Ivy, Poison Oak, Poison Sumac…
What is the most common form of occupational skin disease?
Irritant Contact Dermatitis (ICD)
What type of pathology can you see in chronic ICD?
damage to cell membranes and disruption of the skin barrier (repeated exposures)
What are the two types of Contact Dermatitis?
Irritant and Allergic
What is Eczema (aka Dermatitis)?
A general superficial inflammatory reaction, usually characterized by pruritus and erythema (plus a wide variety of other findings).
What other symptoms may present with SJS or TEN?
Severe pain, fever, tachycardia. Sloughing of epithelium from respiratory and GI tracts. Renal Failure.
What are the indications of Erythema Multiforme Minor?
Presents as target lesions and vesicles predominantly on the extremities. Little mucous membrane involvement and no systemic symptoms. Often occurs recurrently in association with HSV outbreaks.
What is an allergen?
an offending agent that produces a CELL-MEDIATED reaction in some patients, depending on their sensitivity.
What are the symptoms of Lichen Simplex Chronicus?
Either appears as a confluence of small papules, or as a solid plaque. Black skinned patients tend to have a paular pattern. Commonly distributed on the neck, arms or legs, but can be anywhere.
How does the necrotic epidermis from SJS or TEN appear?
Flaccid blisters (with positive Nikolsky sign) When fully detached, exposes a red, oozing dermis that resembles a second-degree burn.
Describe Angioedema.
A swelling of the subcutaneous tissue (usually near eyes and mouth), and mucosa of the respiratory and GI tracts. Usually resolves in 2-4 days.
What findings may indicate Urticaria associated with vasculitis?
If the lesions last longer than 48 hours AND have confounding symptoms, such as arthralgias or fever.
What other conditions are commonly found in patients with atopic dermatitis? (the Triad)
asthma allergic rhinitis
What may be the cause if the patient has angioedema WITHOUT urticaria?
ACE inhibitors. If no history of ACE inhibitors, consider hereditary angioedema (HAE)
Do allergen reactions stay limited to the site of exposure, or spread beyond the exposed sites?
May stay local, May spread beyond the exposed site
What might cause Chronic Urticaria?
An autoimmune disorder or an idiopathic cause.
What is the management of Lichen Simplex Chronicus?
Stop rubbing and scratching! Topical Steroids, most effective under an occlusive dressing Antihistamines at night to prevent scratching.
How is EM Minor treated?
Antivirals to control HSV - Acyclovir, Valacyclovir, or Famciclovir
What age groups do you typically find nummular eczema?
young adults the elderly
How is Allergic Phytodermatitis usually spread?
Through oleoresin (plant oil), not blister fluid. Contaminated skin should be washed within 30 minutes and clothing washed ASAP
How is EM Major treated?
Oral corticosteroids - high dose, then taper down
What are the indication of Erythema Multiforme Major?
Presents as target lesions with vesicles AND bullae on the extremities, also involving the mucous membrane. May take a severe and extensive course associated with detachment of large sheets of skin. Systemic symptoms - fever, prostration (extreme exhaustion) Often results as a DRUG REACTION.
What are the characteristics of Adverse Cutaneous Drug Reactions (ACDRs)?
Erythematous eruptions with abrupt onset. Mostly mild, but severe, life-threatening ACDRs can occur.
What is Hereditary Angioedema (HAE) caused by?
Improper function of protein C1 inhibitor, which can result in swelling of the face, hands, feet, intestinal tract, and trachea
What is an irritant?
an offending agent that is toxic to the skin and produces inflammation in ALL PATIENTS when sufficient concentration is applied.
What are the symptoms of ACD?
Usually progress from erythema, PAPULES, vesicles, erosions, crusts, and scaling Lichenification and excoriation is possible. Pruritis Linear lesions
What type of mechanism may cause urticaria or angioedema?
May be allergic OR non-allergic. Not limited to a drug reaction.
How is dyshidrosis managed?
Topical steroids with an occlusive dressing (gloves) are commonly used to quickly resolve an acute attack.
