Eczema is a broad term used to describe different types of skin conditions. Although there are up to eight different types of eczema, the most commonly recognized forms are Atopic Eczema and Contact Eczema.
Notably, both atopic and contact eczema share the same appearance. In determining both atopic and contact eczema, your doctor will take a detailed medical history from you, including if anyone in your family has been known to suffer from eczema in the past. You will be asked the frequency in which you experience the symptoms of eczema, questions about your current diet, the common areas where it occurs on your body, and how long you have been suffering from the symptoms. Diagnosis differs slightly for atopic or contact eczema.
If you didn’t experience eczema as a baby or from a young age, nor having it run in your family, your doctor will most likely point towards a diagnosis of contact eczema. A clear family history of eczema or eczema symptoms from a young age will lead down the path of diagnosing atopic eczema.
Diagnosing contact eczema
You will be asked to consider which possible substances are causing a reaction, for example, if your occupation is cleaning, perhaps there are chemical products you can rule out. If you work outdoors, then you may have a reaction to a specific type of plant. Your doctor will provide examples, based on his knowledge from previous patients presenting with your similar symptoms.
A patch test may be carried out, which helps to clarify which substances are causing an allergic reaction. This is often performed by a specialist like a dermatologist. The dermatologist will apply tape, usually on your upper back, which contains 25 or more common substances that cause allergies. You will be asked to keep the tape in place for two to three days. Upon return to the clinic, your skin will be examined to see if you had an allergic reaction to specific substances.
Photo patch test for UV sensitivity
Some people have what is called photosensitive dermatitis. This can be an allergy to a particular sunscreen, anti-inflammatory medication or other chemical product once UV light strikes the area of skin where it was applied. Products that contain fragrances or certain additives often trigger an allergic reaction, given it is foreign to the body. In one study of 35 outdoor workers, it was found that 51% had a reaction to a plant called parthenium, which triggered contact dermatitis.
Diagnosing atopic eczema
There is no official test or reliable biomarker that can be used to diagnose atopic eczema. Rather, there are various criteria your doctor will run through with you to determine if you meet enough of those individual factors to be considered a candidate. Many studies are still required in this area in order to find the most effective method in diagnosing atopic eczema, hence why it is considered a complex skin disease.
You will also be asked about any history or presence of asthma or hay fever, given these are common in those that suffer from atopic eczema. If you mention specific foods in your diet, you could be referred to a specialist to undertake a food allergy test. On some occasions, you may also be asked to complete a blood test which could show any irregularities in your immune response system, although this isn’t too common.