On 12/5/2021 I had my Covid-19 vaccine booster (Moderna). Ten days later, on 12/15/2021 I had my hair routinely colored (same salon, same hair dye). That evening, I started getting an itchy scalp, back and neck. I assumed it was a reaction to my hair dye. I washed my hair thoroughly (as I thought some dye may not have been washed out at the salon). Throughout the night though, I began to feel itchy all over my body. Over the next few days, I had extremely itchy rashes and hives in all different areas of my body  predominantly on my torso and neck, but also on my arms, hands, legs, and feet. My skin would suddenly become extremely itchy in a particular area.   As I itched, red raised streaks would appear in the exact location of the scratch. After a while the itch would subside, and the red rash, hives and streaks would disappear, but then another area of my body would feel itchy, and the cycle would repeat itself. It was continuous.   In addition to this skin reaction, I also had an intense heated feeling within my chest - like my blood was boiling! My skin was also extremely sensitive and would react to the slightest pressure on it e.g., from a watch strap, shoe strap, waistband etc.   I tried Benadryl, Claritin, and Calamine lotion but none of these were helping. As a result, I decided to do a virtual doctors call on 12/20/21.  I was prescribed a course of Prednisone (6 x 10mg tablets for 2 days, then 5 x 10mg tablets for 2 days, then 4 x 10mg tablets for 2 days etc...) In addition, I was prescribed Famotidine (1 x 20mg tablet taken twice a day for 14 days) and Cetirizine (1 x 10mg tablet taken once a day for 14 days). Fortunately, the itching and rash/hives significantly calmed down within a day or two.  Towards the end of the course of Prednisone, the itching and rash/hives started to reappear. I booked an appointment with a dermatologist, and she said that I had 'Dermatographia, Dermal hypersensitivity reaction and Pruritus'.  She prescribed Zyrtec for the mornings and Hydroxyzine for the evenings. After a month I came off the Hydroxyzine (as instructed by my dermatologist). I have since tried to come off the Zrytec but the intense itchy feeling comes back within a couple of days. (Even being on the Zyrtec, my skin will still react via a red mark/streak if lightly scratched, but it helps enormously in preventing the itch.)   Although the hair dye may have been a factor, I don't think it was the underlying cause as I have had my hair colored twice over the last few months (same salon, same hair dye) and have not had a reaction.  I can therefore only think that my Dermatographia was caused by the Covid-19 vaccine booster. The hair dye may have triggered the reaction due to my immune system being on such high alert or it may have happened anyway regardless of having my hair colored.    Another reason for thinking that it may be due to the Covid-19 vaccine booster, is that I have since read about a lot of other people having very similar experiences to me with the onset of symptoms (itching/rash/hives) starting approximately a week or two after having their Covid-19 vaccines  which matches to my timing of 10 days. Most of them, like me, are still on medications to keep this Dermatographia skin irritation under control.  It has now been 5 months for me.   One other note to make, is that I did have swollen lymph nodes under the armpit after my booster, which lasted for a few days. This was not as noticeable on my first two doses - which were also Moderna. I also had an overwhelming dizzy/lightheaded feeling when I tried to get up the following morning.  Although I had chills, aching muscles and fatigue after my first two doses, I didn't get such swollen lymph nodes or the intense dizzy feeling.  Although I cannot be certain that my Dermatographia was caused by the Covid-19 vaccine booster, I felt like I should report it as I cannot think of anything else that could have caused it.