This is what I have.

8. CHOLINERGIC URTICARIA

A common condition in young adults with intensely itchy and short-lived eruption developing in response to sweating, exercise, emotion and hot foods. It is postulated that an increase in blood temperature triggers a neural reflex which releases acetylcholine from sympathetic nerve endings, in turn activate the mast cell to degranulate. Characteristic small wheals, less than 2 mm in diameter with surrounding red halo are more profuse on the upper trunk and proximal parts of the upper limbs. Thus it is also called micropapular urticaria. Associated systemic symptoms include faintness, headache, wheezing and palpitation.

Diagnosis is established from the history and the finding of characteristic rash during an attack. The rash can also be brought up on exercise or whole body warming. These lesions can often be reproduced by intradermal injection of cholinergic drugs, e.g., metholyl or acetylcholine.

Treatment is unsatisfactory. Patients, especially those with associated systemic symptoms, should be told to avoid situations that can precipitate an attack. Some patients improve with antihistamine therapy. This can be taken regularly or at times when they anticipate attacks. Fortunately for most patients the condition tends to improve spontaneously.