I'm not in the medical profession. My experience with eczema culminates in 30+ years of personal experience due to my mother's years of suffering with eczema. Although the medical terminology and research findings (such as the one you presented) seem impressive, I wasn't impressed with the treatment that my mother received from the medical community regarding her eczema. As a result, and when my nieces were born and diagnosed with eczema (the atopic dermatitis form), I decided to take matters into my own hands regarding their treatment.
What I observed with my mother is that the medical community went no further than diagnosis when treating my mother's eczema symptoms. In other words; after diagnosis, they'd simply respond with symptom suppression and never address the root cause of the symptom or disease. My Grandmother called it "book smart, without common sense (knowledge, without wisdom)". She would say things like, "they're so smart, they're stupid"; meaning that they had overcomplicated that which was simple. It turned out that in my mother's case, she was right.
We fear what we don't understand. I needed to understand what the body was messaging with the symptom of eczema; so I studied the skin and its functions. Two things happened immediately in my study; I was filled with optimism, and at the same time, anger. I was optimistic because the solution to bring forth the healing seemed simple. The anger came; because if my theory proved to be correct, then my mother's suffering for over 30+ years could have easily been ended in the first year. My theory proved to be correct and my oldest niece has been eczema free for five years now, without the use of harmful medications. The middle niece has been eczema free for 3 years. The youngest niece had a short bout with eczema for 3 days when she was nine months old. She's a year old now and also eczema free. By the way, the two oldest nieces suffered severe (total body) eczema flareups.
We cut through the medical jargon to get to the basic facts: "what is the diagnosis?", "what is the message that the body is sending through the symptoms?", and "how do we go about addressing the symptom's message?". Where we differed in our approach from that of the medical community is that we chose to address the root cause of the symptom; as opposed to the medical communities approach (in our mother's case) of suppressing the symptom. Not every one in the medical community promotes treatment of disease through suppression - this just happened to be my mother's case; and unfortunately the case for many eczema sufferers. This type of approach (symptom suppression) is also the reason for the temporary relief and longterm frustration that is endured by many eczema sufferers. My nieces are living proof that such treatment is unnecessary.
My intention was not to be long winded in my questions and answers to you; however, I feel that you need to understand the person behind the name "aunty" and to clarify any misconceptions of me regarding the medical profession. As a layman, I want people to understand that they don't have to be intimidated by a lack of a medical degree in order to take back control of their health.
Dermatitis and eczema are interchangeable terms that usually refer to inflammation of the skin. Eczema is taken from the Greek "ekzein", meaning "to boil over or break out". There are many forms or types of eczema or dermatitis. Perivascular dermatitis refers to the region of the breakout. Contact dermatitis refers to a localized reaction that occurs when the skin has come in contact with an allergen. Erythema refers to the redness of the skin. Erythema can occur from exposure to the sun, a slap to the skin, or as a symptom of disease. The redness in the skin occurs when there is an increase in the amount of blood present in the capillaries (small blood vessels) of the skin. Pruritus refers to the itching of the skin. Both 'erythema' and 'pruritus' are common eczema symptoms. When layman hear the terms 'erythema' and 'pruritus', it sounds like horrible diseases. When they are defined in our common english (laymans terms), "redness of the skin" and "itching", they don't carry that same fear or horror. In basic terms and to answer your question, "what is perivascular dermatitis?", your doctor diagnosed you with eczema.
Regarding the contact dermatitis that occurred on your foot from the leather strap, you might consider trying vitamin E oil. Whole Foods Market is a good place to visit to find such products. Also, I really think that you need to schedule another doctors appointment to get a proper diagnosis regarding the patches on your legs (preferably with a different physician this time - 2nd opinion).