Rash on buttocks

I have a puzzling skin problem.
I have extremely sensitive skin - I suffered from eczema as a child and continue to suffer from keratosis pilaris.I am also sensitive to many fragrances, pollens, chemicals etc.
I have been having an outbreak of a rash on my buttocks coinciding with the third week of my monthly period for the past 2 months (these are the first 2 periods I have had after giving birth to my daughter). It begins as extremely dry skin which is itchy and burning, this then breaks out in lots of tiny little red barely raised that spread all over my buttocks. Some of these bumps become bigger red pimple like bumps and occasional rough red patches of skin (about 1cm). Occasionally these are pustule like - especially where the skin is most irritated, but never fluid filled. I have had 2 of these 'pustules' swab cultured for herpes the day they have appeared and both have been negative. The rash covers most of my buttocks, but the larger papules and patches occur in different places and keep appearing over a couple of weeks.
The rash is quite itchy and burns - especially before the rash appears and even for a few days after.
I suffer from dry skin on my vulva around this time as well - the skin is always papery and sometimes this flakes (in areas where my clothing rubs). A couple of times a fissure has developed where the skin is flaky, which seems to flare up and not completely heal before flaring up again (this swabbed negative for herpes).
I can recall this buttock rash appearing for most of my adult life, my mother remembers it starting as an early teenager (when I was definitely not sexual active in anyway).

I also suffer from dry skin and patches of dermatitis on my fingers, thighs, the sides of my torso. I have chronically cracked and fissured heels and big toes.

My question is - do these symptoms sound like atopic dermatitis? If so, could it be a hormone related problem?
Or could it be that I am suffering from herpes?
Thankyou

[Bhupinder Kaur, MD]

Hello,
These do not sound like herpes.As I was going through your post,two possibilities crossed my mind.First is of hives or urticaria and second is of atopic dermatitis/eczema.

Hives (medically known as urticaria) are red, itchy, raised areas of skin that appear in varying shapes and sizes. They are of two types:acute and chronic(when hives persist for more than 6 weeks). The most likely triggers for acute urticaria are allergies to pets, horses, latex and foods, such as shellfish and nuts,bee or wasp stings,allergies to medicines,viral infections,dental and sinus infections, fungal infections, blood transfusions and vaccines.

The cause of chronic urticaria is often more difficult to identify. Most cases are called chronic idiopathic urticaria, which means they're caused by the body's unexplainable development of antibodies to itself (auto-antibodies).

Atopic dermatitis is an inflammatory, chronically relapsing, non-contagious and pruritic skin disease.

I would suggest a consultation of an allergist/dermatologist and get these two evaluated.Treatment will depend on the confirmation of diagnosis.

Hope it helps.Take care and pls do keep me posted on how you are doing or if you have any additional doubts. Kind regards.