GENERAL INFORMATION
• Atopic dermatitis is an inflammatory skin disease with recurrent attacks and a chronic course. It is characterized by erythema, edema, pruritus, exudation and crusting, scaling.
80% of cases with atopic dermatitis are accompanied by asthma and/or allergic rhinitis.
80% of atopic dermatitis regresses as they get older.
80% of patients have high serum IgE.
pathogenesis
• There is spongiosis and significant intracellular edema in the epidermis. Decreased lipid levels in the epidermis (xerosis).
• Atopic eczema (70-80%): IgE mediated.
• Non-atopic eczema (20-30%): Not IgE mediated.
In Non atopic eczema, compared to atopic eczema; IL-4 and IL13 levels are lower, while IL-17 and IL-23 levels are higher.
Both types are characterized by eosinophilia.
• Th2 lymphocyte plays a more prominent role in acute AD, and Th1 lymphocyte plays a more prominent role in chronic AD.
• IL-4 and IL-13 cytokines released from Th2 lymphocytes are increased in acute AD.
• While IL-4 and IL-13 cytokines are decreased in chronic AD, interferon gamma, IL-12, IL-5, GM-CSF cytokines are increased. غ
• Eosinophil and macrophage infiltration increases in chronic AD.
• Increase in T lymphocytes expressing IL-22 increases the severity of AD.
• Mutation in the Flaggrin gene (the protein responsible for skin barrier functions) was detected in S0% of the patients (especially in severe cases).
Clinical Findings
• The main symptoms are severe itching, chronic and recurrent course, typical morphology and distribution of skin lesions, family history of atopic disease.
• The disease begins in the first 2-3 months. It first begins on the cheeks, in the form of erythematous and purulent patches. It occurs on other parts of the face, the nape, wrists, arms, abdomen, and extensor surfaces of the extremities. Skin dryness is very common.
• Healing begins at 3-5 years of age and completely relieves at >5 years of age. Lesions continue in the antecubital region, popliteal fossa, wrists, behind the ears.
• While mainly the extensor faces are involved in the infant, the lesions are mainly seen on the flexor faces after 5-6 years of age.
• As the age progresses, the skin becomes dry and thickened and there is a white appearance called "atopic dermatitis mask" on the skin.
• 40% of children with moderate to severe atopic dermatitis have food allergies. May be allergic to cow's milk, soy and peanuts, most commonly egg white.
Least involved areas in atopic dermatitis
• Diaper area
• Palms and soles
• Mucosa
Lab
• Allergen-specific TH2 lymphocyte counts that secrete interleukins such as IL-3, 4, 5 have increased. It could be eosinophilia. The B cells of these patients secrete large numbers of IgE.
Diagnosis
• Among the diagnostic criteria, there should be 3 minor findings along with 3 major findings.
Full criteria for atopic dermatitis
Major
- Itching , Typical location:
Eczema on the face and extensor regions (infant-child)
Flexural eczema (adolescent)
- Chronic and recurrent dermatitis
- History of atopic disease in the child and family
Minor
- Dryness of the skin (xerosis)
- Skin infection
- Hand-foot nonspecific dermatitis
- White dermographism
- Increase in serum lgE
- Anterior subcapsular cataract, keratoconus
- Ichthyosis, palm line enlargement, keratosis pilaris
- Positive early hypersensitivity test on the skin
- Early start
- Dennie-Morgan detention lines
- Facial erythema and pallor
- Nipple eczema
- Presence of environmental and emotional factors
Differential Diagnosis of Atopic Dermatitis
• The most common skin infection agent accompanying atopic dermatitis is S. aureus.
