Allergic Dermatological Disorders

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Allergic Dermatological Disorders

• Mark D. Goodwin, Col, USAF, MC
• Program Director, Family Medicine Residency
• 55 MDG Director, Medical Education
• Chief, Allergy/Immunology Clinic

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Or

• The Red Itchys!

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Allergic Skin Disorders

• Urticaria
• Allergic Contact Dermatitis
• Atopic Dermatitis

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Allergic Skin Disorders

• Definitions
• Clinical manifestations
• Demographics/Epidemiology
• Pathophysiology
• Evaluation
• Treatment

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Urticaria

• Transient localized areas of edema within
  skin due to leaking of capillaries into
  connective tissue
• Superficial dermis lesions- wheals
• discrete, generalized, papular erythematous
  central pallor, blanching anywhere on the body
  not on mucosal surfaces
• Spread by scratching coalesce
• Individual lesions last 1-2 hrs lt24 hrs
• Major clinical feature- pruritus!

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Angioedema

• Urticaria in deeper layers of dermis!
• Nonpitting, well-defined induration most commonly
  of head, neck, hands, but can occur anywhere and
  frequently involves mucosal tissue
• Swelling more prominent in looser skin- scrotum,
  labia, lips, tongue, eyelids
• Not limited to dependent areas, asymmetrical
• Typically painful, rather than pruritic
• Skin colored, occasionally pink slower in
  onset/resolution than urticaria

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Urticaria/Angioedema

• Acute
• lt6 weeks duration
• Most common identifiable cause is viral infection
  (EBV) gtgt meds, idiopathic, foods, insect sting
• More common in children and young adults
• Remember- acute reaction can be early s/sxs of
  anaphylaxis!!

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Urticaria/Angioedema

• Chronic
• gt6 weeks duration at least 2x/week
• 25 of urticaria cases
• 50-80 of chronic cases idiopathic
• Up to 30 is physical urticaria
• MF 12 (middle-aged females)
• lt2 related to food allergens in adults
• Rarely IgE mediated
• Affects 0.1 to 3 of population

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Urticaria/Angioedema

• 14-25 of US population lifetime risk
• Preschool children is 6 to 7
• 17 in children with atopic dermatitis
• Urticaria and angioedema occur concomitantly in
  40-50 of patients
• 40 have only urticaria
• 10-20 have isolated angioedema

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Classification of urticaria and angioedema

• Immune-mediated
• IgE mediated hypersensitivity
• Complement-mediated
• Ab-Ag complexes activate complement cascade
• Nonimmune-mediated
• non-IgE mediators degranulate mast cells
• Autoimmune-mediated
• degranulation of mast cells by auto-antibody

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Classification of urticaria and angioedema by
etiology

• Drugs and other medical agents
• Foods and food additives
• Environmental allergens (inhaled, ingested,
  contact)
• Insects (stings, bites, and contact)
• Systemic illness
• Vasculitic and autoimmune diseases
• Infections (viral, bacterial, fungal, parasitic)
• Malignancies
• Physical stimuli (thermal, mechanical, solar,
  exercise, aquagenic)
• Genetic
• Mast cell proliferation
• Idiopathic

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Etiology of Chronic Urticaria/Angioedema
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Common Causes of Urticaria/Angioedema

• Immunologic causes
• Type I IgE-mediated
• Type II cytoxic antibody-mediated transfusion
  reaction
• Type III antigen-antibody mediated serum
  sickness reaction
• Type IV delayed hypersensitivity medication,
  food handling, or exposure to animals

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Common Causes of Urticaria/Angioedema

• Autoimmune disease Hashimotos disease, systemic
  lupus erythematosus, vasculitis, hepatitis
• Infection viral (e.g., cytomegalovirus,
  Epstein-Barr, hepatitis), parasitic, fungal, or
  bacterial
• Malignancy more likely to present with isolated
  angioedema

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Common Causes of Urticaria/Angioedema

• Nonimmunologic causes
• Direct mast cell degranulation opiates,
  vancomycin, ASA, radiocontrast media, dextran,
  muscle relaxants, NSAIDs, ACE-I
• Foods containing high levels of histamines
  strawberries, tomatoes, shrimp, lobster/octopus,
  cheese, spinach, eggplant, wines, flavor
  enhancers, dyes etc.

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Common Causes of Urticaria/Angioedema

• Nonimmunologic causes
• Physical stimuli
• Appear within 10 min clear lt60 min
• Dermatographism
• Aquagenic
• Vibratory
• Papular
• Solar
• Cold-induced
• Cholinergic
• Delayed pressure

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Papular Urticaria
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Solar Urticaria

• Sensitivity to specific wavelengths
• Six types
• Type VI associated
• with porphyria
• Test Light exposure

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Cold Urticaria
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Dermatographism
Cholinergic Urticaria
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Common Causes of Urticaria/Angioedema

• Autoimmune Urticaria
• 30-60 idiopathic urticaria due to autoimmune
• Not autoimmune disease like SLE
• ASST test
• Genetic disorders
• HAE types 1,2
• s/sxs by age 5 yrs in 40
• Triggered by trauma, infection, stress

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Contact Urticaria Syndrome

• Skin contact with compounds elicit wheal/flare
  response
• Nonimmunologic type
• Immunologic type
• Protein contact dermatitis- eczematous skin
  exposed to certain foods (fish, garlic, onion,
  chives, cucumber, parsley, tomato), animal (cow
  hair and dander), or plant substances
• No standard test battery

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Pruritic Urticarial Papules and Plaques of
Pregnancy (PUPPP)

• Urticaria in and around
  abdominal striae
• Lesions may spread to extremities
• Face, palms and soles usually spared
• Usually begins in 3rd trimester, may occur
  postpartum
• Often resolves a few weeks after
• delivery

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Pathophysiology of Urticaria
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Differential Diagnosis

• Contact dermatitis
• Erythema multiforme
• Bullous pemphigoid
• Dermatitis herpetiformis
• Urticarial vasculitis
• Arthropod bites

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Dermatitis herpetiformis
Erythema multiforme
Bullous pemphigoid
Urticarial vasculitis
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Evaluation- History

• History!
• Onset, timing wrt food, drugs, travel infections
  etc.
• Previous history of same lesions
• Treatment to date
• Physical triggers
• Other/Associated symptoms
• Family history of angioedema, sudden death
• Exposures (insects, occupational)
• Other diseases, allergies
• Thyroid dz, Diabetes, Malignancy, CVD

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Physical Exam

• Dermatographism
• Lymphadenopathy
• Goiter
• Organomegaly
• Abdominal masses
• Urticaria pigmentosa
• Vasculitis
• Tinea Pedis, Onychomycosis

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Screening labs

• No labs routinely for acute urticaria or mild
  ordinary chronic urticaria responding to
  antihistamines
• Chronic urticaria/angioedema baseline labs
• CBC with differential
• ESR
• UA
• LFTs
• TSH if chronic and not responding

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Directed labs

• Stool for OP
• ANA
• Cryoglobulins
• Hepatitis panel
• Anti-thyroid antibodies
• C1 Inhibitor
• Level
• Functional assay

• CH50, C3, C4
• C1q level
• Food skin tests and elimination diet
• Age appropriate cancer screening (PSA, PAP,
  colonoscopy, mammo, CXR)

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Tests for Physical Urticaria

• Light exposure
• Pressure application
• Lab vortex
• Ice cube test
• Exercise (room temp 85 degrees F)

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Treatment

• Removal of stimulus
• Avoidance of precipitators
• Antihistamine prophylaxis
• Mainstay of therapy
• Use round the clock, NOT prn
• Second generation Antihistamines

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Treatment

• Addition of H2 antihistamine
• For Breakthrough symptoms
• HS sedating antihistamine
• Singulair/LTRA
• Doxepin
• Corticosteroids, methotrexate, cyclosporine

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Treatment

• Not IT!!!

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Prognosis for Chronic Idiopathic
Urticaria/Angioedema

• 50 resolve within 3-12 months
• 40 resolve within 1-5 years
• 80 resolve within 10 years
• 1-2 persist for 20-25 years
• 40 with chronic urticaria will have at
  least 1 more episode in their
  lifetime

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Patient Education in Chronic Idiopathic Urticaria

• May not become completely hive-free
• Reassurance
• Resist patients' urging for more tests
• Resist frustration to do something

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Summary

• Urticaria- symptom not disease
• Laboratory workup rarely necessary
• Antihistamines mainstay of therapy
• Allergy consult if
• Acute with life threatening symptoms
• Chronic gt 6 weeks duration
• Dermatology consult if vasculitic

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Contact Dermatitis

• Contact dermatitis
• Allergic (ACD) and irritant etiologies (ICD)
• Most common occupational disease in US
• Accounts for 90 of skin disorders acquired in
  the workplace
• 3000 of 6 million chemicals can cause ACD
• Occupationally related annual cost of ACD
  includes 250 million in lost productivity,
  medical care, and disability payments

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Allergic Contact Dermatitis

• Acute ACD
• Pruritic vesicles, edema, erythema, bullae at
  site of exposure
• Chronic ACD
• Crusting leads to lichenifcation and scale
• One uniformly present feature of ACD is pruritus,
  without which the diagnosis of ACD is virtually
  excluded!

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ACD Pathophysiology

• Prototypic delayed or cell-mediated
  hypersensitivity reaction
• itch-scratch cycle
• Sensitization- hapten-protein complexes to
  Langerhans cells
• Elicitation- allergen presented to Th1
  inflammatory cascade follows

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ACD Evaluation

• History
• History
• History
• Exam
• Patch testing

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ACD Evaluation

• Differential Diagnoses
• ICD
• Atopic Dermatitis (AD)
• Endogenous dermatoses
• Phototoxic reaction
• Contact Urticaria
• Skin infections

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ACD Common allergens

• Poison Ivy
• Metals
• Medications
• Latex/rubber
• Formaldehyde/fragrances

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ACD Prevention and Treatment

• Identify
• Avoid
• Barriers
• Medications
• Topical
• Oral

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ACD Prevention/Treatment and IT?
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ACD Summary

• Allergic (ACD) and irritant etiologies (ICD)
• Most common occupational disease in US
• 90 of workplace skin disorders
• Type IV hypersensitivity
• 5 common allergens
• Avoidance is best treatment!

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Atopic Dermatitis

• Genetically transmitted, chronic inflammatory
  condition
• Most common chronic, relapsing skin d/o in
  infants/children
• 15-20 children
• 1-3 adults
• Atopic March
• Atopic Eczema vs. nonatopic eczema

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AD Features

• Cardinal feature- pruritus that disrupts
  sleep/ADLs
• 3 distinct clinical phases
• Infantile
• Childhood
• Adulthood
• Diagnosis
• Pruritus
• Eczematous dermatitis in proper distribution
• Chronic/relapsing course

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AD Features
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AD Features

• Essential features
• Pruritus, chronic or relapsing dermatitis
• Facial/extensor eczema in infants/younger
  children
• Flexural eczema in older children and adults
• Frequently associated features
• Personal/family history atopic disease early age
  onset
• Cutaneous infections nonspecific dermatitis
  hands/feet
• Raised serum IgE Positive PST, Xerosis
• Other features
• Ichthyosis, palmar hyperlinearity, keratosis
  pilaris, Pityriasis alba
• Nipple eczema, facial erythema or pallor, orbital
  darkening
• White dermatographism, delayed blanch response,
  keratoconus
• Anterior subcapsular cataracts, Dennie-Morgan
  infraorbital folds

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AD Pathophysiology

• Dys-regulation of Th2 biased immune response to
  environmental stimuli
• Genetics
• Skin barrier dysfunction

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AD Pathophysiology

• Environment
• Irritants
• Allergens
• Infections

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AD Differential Dx

• Other forms eczema
• Immunodeficiencies
• Infections
• Neoplastic dz
• Metabolic dz
• Infants

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AD Evaluation

• No objective diagnostic lab test
• Food challenge
• SPT/PST
• APT
• Serum IgE levels
• Food specific IgE levels
• Punch biopsy

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AD Treatment

• Accurate diagnosis!!
• Patient education
• Skin hydration
• Control of pruritus and infections
• Appropriate use topical anti-inflammatory
  medications
• Id/elimination of exacerbating factors
• Systemic Tx

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AD Treatment
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AD Treatment
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AD Prevention

• Formula vs. breast feeding
• Probiotics
• The Future ?
• Current drugs
• New approaches

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AD Summary

• Most common chronic, relapsing skin d/o in
  infants/children
• Atopic March
• Distinct phases
• Complex pathophysiology
• Treatment has 4 main goals

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