I would like to say that dermographia is a sign of angioedema.
Both forms of skin wheals are discussed in this paper.
http://www.aacijournal.com/content/5/1/10
The histamine type is far more common, than the bradykinin type, so often doctors don't think of the latter at all.

There is acquired angioedema (and I am not speaking of hives), but of another biogenic amine involved in angioedema caused by another biogenic amine called bradykinin.

Some people get acquired angioedema from the ACE family of blood pressure drugs. There are several types of inherited angioedema, (called HAE), and one is involved with female hormones.

When I was taking lisinipril for blood pressure, I developed over time a huge reaction involving the nerves, and GI tract, breathing and swelling of various body parts for no reason.

My doctor finally decided I had HAE and always had it. The drug only exacerbated the symptoms and made them more severe.

These links explain it better than I can. Most doctors don't know about this unless they have taken continuing education courses about it. It was only elucidated in the 1970's, and hence is not in most course work in medical schools.

http://www.haea.org/patients/what-is-hae/
This link is the most comprehensive.

http://www.webmd.com/allergies/angioedema-hereditary

The word angioedema is also used to describe hives and other issues involving histamine. The angioedema I am writing about is mediated by bradykinin...which also causes swelling and things like dermographia. Any stimulus or pain can cause fluid to leak out into the skin and in people with HAE, the enzyme C-1 inhibitor is low and cannot metabolize excess away...so spells occur. In females...estrogen is implicated. One treatment is to use androgens to suppress this.

I had a simple IV (injecting a contrast agent) for an echocardiogram 2 yrs ago ..it was placed in the back of my hand. It lasted all of 1/2 hr and was removed. That resulted in my left hand swelling up for over 2 months! That is only one example.

Doctors may think HAE patients are hypochondriacs, so it might never be diagnosed properly. And doctors may not even understand HAE. When the swelling happens, there is numbness, and or prickling or itching as well. My severe final reaction involved whole body agony for 2 days! For years my symptoms were explained as "asthma" and GI problems.