It is quite easy to identify the major differences between atopic and contact dermatitis. But in the cases that are not so obvious, identification becomes difficult. In some cases, there is a possibility that the individual may be affected by both types of this condition, making it all the more harder to diagnose. Between the similarities and differences lie the diagnosis of these conditions, especially when the causes for eczema and atopic dermatitis have to be identified.

1. What are the similarities?
Eczema is not regarded as a diagnosis but rather a form of a rash that results from the occurrence of atopic and contact dermatitis. Eczema is more of an umbrella term under which these two forms of dermatitis can occur in isolation or in combination.

In general, the stages of eczema is threefold and different. Acute eczema is the occurrence of vesicles, i.e., itchy blisters on a red and inflamed skin. Subacute eczema is when the skin is itchy, dry, flaky, oozing, or crusting. Chronic eczema is defined by the appearance of lichenification, wherein the skin becomes leathery and thickened due to the action of repetitive or chronic scratching.

The best way to diagnose the similarities between both atopic and contact dermatitis is to perform a biopsy. This will help study the epidermis’ spongiotic changes, which refers to the swelling that is essentially happening under the skin. However, this process will not essentially help pinpoint which of these types the individual is suffering from.

2. What are the differences?
In terms of eczema vs atopic dermatitis vs contact dermatitis, the differences have to be studied and analyzed to see which of the conditions the individual is affected by. Filaggrin is a protein that undergoes genetic mutation in case the individual has atopic dermatitis. This process of mutation of the protein will end up disrupting the barriers that are present between the epidermal skin cells. As a result, there would be dehydration of the skin, and it can end up being irritated from allergies, specifically aeroallergens such as dust mites or pet dander. This will end up in scratching of the skin leading to more inflammation in the affected region. Another possible cause for atopic dermatitis is the consumption of foods that end up with the T-lymphocytes in the body causing allergic inflammation.

In the case of contact dermatitis, the cause is more straightforward exposure to any form of chemicals that are irritants. In most cases, it is poison oak that has been found to be a direct cause, apart from other agents such as cosmetics, hair dyes, and nickel. In this case too, the T-lymphocytes end up causing allergic inflammation as a natural reaction to the allergen attack.

The main difference in eczema vs atopic dermatitis vs contact dermatitis lies in the age of the individual. While eczema is the same reaction in any age group, those below the age of 5 are affected by atopic dermatitis; whereas contact dermatitis is more common in adults.