Dermatitis, Atopic
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Basics
Description
- A chronic, relapsing, pruritic eczematous condition affecting characteristic sites
- Early onset cases have coexisting allergen sensitization more often than late onset.
- Clinical phenotypical presentation is highly variable, suggesting multifactorial pathophysiology.
- May have significant effect on quality of life for patient and family-recurrent symptoms affect lifestyle and mental health.
Epidemiology
- 45% of all cases begin in the first 6 months of life with 95% onset prior to age 5 years.
- 50–66% of affected children will have a spontaneous remission before adolescence.
- Also, may have late-onset dermatitis in adults or relapse of childhood condition—primarily hand eczema
- Darker pigmented individuals are affected more often than lighter skinned individuals.
- 60% if one parent is affected; rises to 80% if both parents are affected
Incidence
On the rise over the past 3 decades in industrialized countries.
Prevalence
Approximately 13% of children and 7–10% of adults in the US (1)
Etiology and Pathophysiology
- Two main hypothesis: immunologic with unbalanced immune response and/or skin barrier dysfunction
- Alteration in stratum corneum results in transepidermal water loss and defect in barrier function.
- Epidermal adhesion is reduced either as a result of (i) genetic mutation resulting in altered epidermal proteins or (ii) defect in immune regulation causing an altered inflammatory response.
- Interleukin-31 (IL-31) upregulation is thought to be a major factor in pruritus mediated by cytokines and neuropeptides rather than histamine excess.
Genetics
- Recent discovery of association between atopic dermatitis (AD) and mutation in the filaggrin gene (FLG), which codes for a skin barrier protein
- Both epidermal and immune coding likely involved
Risk Factors
- “Itch–scratch cycle” (stimulates histamine release)
- Skin infections
- Emotional stress
- Irritating clothes and chemicals
- Excessively hot or cold climate
- Food allergy in children (in some cases). Studies of breastfeeding conveying decreased risk versus increased risk are mixed in conclusion (2)[C].
- Exposure to tobacco smoke
- Some evidence suggests that repeated exposure to “hard” water may exacerbate condition.
- Family history of atopy
- Asthma
- Allergic rhinitis
Commonly Associated Conditions
- Food sensitivity/allergy in many cases; strong association with asthma and allergic rhinitis
- Association with both cutaneous and extra-cutaneous infections: URI, OM, UTI, cellulitis, erysipelas, zoster, endocarditis, MRSA, MSSA, pharyngitis, and rarely sepsis (1)
- Hyper-IgE syndrome (Job syndrome)
- AD
- Elevated IgE
- Recurrent pyodermas
- Decreased chemotaxis of mononuclear cells
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Basics
Description
- A chronic, relapsing, pruritic eczematous condition affecting characteristic sites
- Early onset cases have coexisting allergen sensitization more often than late onset.
- Clinical phenotypical presentation is highly variable, suggesting multifactorial pathophysiology.
- May have significant effect on quality of life for patient and family-recurrent symptoms affect lifestyle and mental health.
Epidemiology
- 45% of all cases begin in the first 6 months of life with 95% onset prior to age 5 years.
- 50–66% of affected children will have a spontaneous remission before adolescence.
- Also, may have late-onset dermatitis in adults or relapse of childhood condition—primarily hand eczema
- Darker pigmented individuals are affected more often than lighter skinned individuals.
- 60% if one parent is affected; rises to 80% if both parents are affected
Incidence
On the rise over the past 3 decades in industrialized countries.
Prevalence
Approximately 13% of children and 7–10% of adults in the US (1)
Etiology and Pathophysiology
- Two main hypothesis: immunologic with unbalanced immune response and/or skin barrier dysfunction
- Alteration in stratum corneum results in transepidermal water loss and defect in barrier function.
- Epidermal adhesion is reduced either as a result of (i) genetic mutation resulting in altered epidermal proteins or (ii) defect in immune regulation causing an altered inflammatory response.
- Interleukin-31 (IL-31) upregulation is thought to be a major factor in pruritus mediated by cytokines and neuropeptides rather than histamine excess.
Genetics
- Recent discovery of association between atopic dermatitis (AD) and mutation in the filaggrin gene (FLG), which codes for a skin barrier protein
- Both epidermal and immune coding likely involved
Risk Factors
- “Itch–scratch cycle” (stimulates histamine release)
- Skin infections
- Emotional stress
- Irritating clothes and chemicals
- Excessively hot or cold climate
- Food allergy in children (in some cases). Studies of breastfeeding conveying decreased risk versus increased risk are mixed in conclusion (2)[C].
- Exposure to tobacco smoke
- Some evidence suggests that repeated exposure to “hard” water may exacerbate condition.
- Family history of atopy
- Asthma
- Allergic rhinitis
Commonly Associated Conditions
- Food sensitivity/allergy in many cases; strong association with asthma and allergic rhinitis
- Association with both cutaneous and extra-cutaneous infections: URI, OM, UTI, cellulitis, erysipelas, zoster, endocarditis, MRSA, MSSA, pharyngitis, and rarely sepsis (1)
- Hyper-IgE syndrome (Job syndrome)
- AD
- Elevated IgE
- Recurrent pyodermas
- Decreased chemotaxis of mononuclear cells
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