Atopic dermatitis is a clinical diagnosis with no definitive laboratory test. Diagnosis is usually done by skin inspection. But to differentiate there are following criteria have been mentioned below:
Diagnostic criteria for atopic dermatitis:
Pruritis and at least three of the following are required:
- History of itch in skin folds ( or cheeks if < 4 years).
- History of asthma/ hay fever ( or in 1st-degree relative if <4 years)
- Dry skin ( xeroderma)
- Visible flexural eczema ( cheeks, forehead, outer limbs if < than 4 years)
- Onset in first 2 years of life.
Patch tests
These are performed on dermatitis, which is useful to determine the allergen that has caused the allergic reaction.
IgE and specific IgE tests
These are not routinely undertaken in atopic dermatitis.
Prick tests
These are not usually helpful in atopic dermatitis.
Bacterial and viral swabs for microscopy and culture
These are useful in secondary infection.
herpes simplex virus
Individuals with atopic dermatitis have an increased susceptibility to the herpes simplex virus and are at higher risk of developing a widespread infection, eczema herpecticum.
Skin scraping
It is to rule out secondary fungal infection should be considered.
Skin biopsy
It is usually not required unless there is diagnostic doubt, e.g. of drug adverse effect or cutaneous lymphoma.
For more information, you can visit Mayoclinic and Medscape.
