[Sarann]

The dog wasn't wearing a service vest or any other apparatus indicating it was "on duty".
This is the reply I just received for my complaint:
I write in reference to your message submitted on our website on the 26 October 2013 regarding your flight from Atlanta to Brussels on the 17 October 2013. KLM act as the customer service representative for Delta Air Lines in Europe. Under a set of strict rules, and with certain destinations excepted, Delta Air Lines allows passengers to bring their pets in the cabin on its flights. Although I fully understand that this caused you some discomfort due to your allergic condition, I regret to inform you that we cannot presently guarantee pet-free flights on routes where this is allowed. On request, we will try to accommodate alternative seating arrangements on board. However, this is subject to passengers’ voluntary acceptance. I have forwarded your comments to our product developers. We use all feedback received from customers in our continuous evaluation of our services. Thank you for contacting KLM and Delta Customer Care. Yours sincerely, B. Vatn Customer Care Europe It is not possible to reply to this e-mail address. Should you need to contact us again, please do so via our web form which you can find on www.klm.com.