Atopic Dermatitis Flashcards
What is atopic dermatitis?
Also called eczema, is a chronic, Pruritic, Relapsing inflammatory skin condition
- It is one of the most common and stressful of all chronic skin disorders in children
History taking in atopic dermatitis?
- Environmental interactions
- Infectious triggers
- Higher social economic class
- Family history of atopy
- Predisposed to the development of allergy and allergic rhinitis (atopic march)
- Asthma develops in up to 50% of children
- Anxiety and stress
- Climate (extremes of temperature and humidity)
- Irritants, allergens, and infections
- Coexisting food allergies (30% of patients)
Pathogenesis?
- Multifactorial
- Complex interplay of
- Genetics
- Immunologic abnormalities
- Impaired skin barrier function
Describe the pathogenesis of AD?
- There is an exaggerated cutaneous inflammatory response to environmental triggers, including irritants and allergens
- Prevalence is lower in areas where industrial pollution is less and where eosinophil-mediated infections such as helminthic infections are endemic
- It is now known that mutations in filaggrin, in addition to causing ichthyosis vulgaris, cause the barrier dysfunction, which is characteristic of atopic dermatitis in about 50% of patients
Describe how external factors cause AD?
- In genetically predisposed individuals, external factors including environmental irritants and allergens, bacteria, fungi, viruses, and foods trigger the differentiation of Th2 lymphocytes from Th0 lymphocytes and the release of acute inflammatory mediators (IL-4, 5, 13, 31)
- In chronic disease Th1 lymphocytes are activated and chronic inflammatory mediators are upregulated
What are the external factors that aggravate AD?
- Rubbing or scratching
- The resultant scratching leads to acute and chronic changes typical of atopic dermatitis - Contact with saliva or acidic foods
- Soaps and detergents
- Wool or other harsh materials
- Fragranced products
- Sweat
- Highly chlorinated pools
- Low humidity
- Tobacco smoke
- Dust mites, animal dander, environmental pollens, and molds
Genetic factors that cause AD and their effect?
Positive families history of allergic rhinitis or asthma
- One-third of the children develop atopic dermatitis
Common history of patients with atopic dermatitis?
- 1/3 have personal history of allergic rhinitis or asthma
- 2/3 have family history of atopic dermatitis
- ½ ultimately develop allergic respiratory symptoms
Infantile phase of AD?
6 weeks to 2–3 years
Describe the skin rash of AD?
dry, red, itchy papules and plaques, may ooze and crust
Distribution of rash?
- Symmetrical on cheeks
- Forehead
- Scalp
- Trunk
- Extensor surfaces of the extremities
- The diaper area is usually spared
Lesion distribution in the infantile group (0-3 years)?
face and extensor surfaces; often generalized
Lesion distribution in the childhood group (4-10 years)?
- flexural surfaces (antecubital and popliteal fossae)
- wrists, ankles, hands, and feet
Lesion distribution in adults?
- Flexural areas
- neck, the face, hands, fingers, toes, and the upper arms and back
What is lichenification?
- thickening of the skin due to chronic scratching
- post-inflammatory hyperpigmentation