A 22 year old woman developed small itchy wheals after physical exertion, walking in the sun, eating hot spicy food and when she was angry. The most likely diagnosis is:

Ans. is 'd' i.e. Cholinergic urticariaRef: Roxburgh 16th/e p 66-69, Pasricha 4th/e p 144, 147, 148, 145; Skin Behl 8th/e p 119-121UrticariaIt consists of raised erythematous skin lesions, that are markedly pruritic evanescent and are generally worsened by scratching.Cholinergic urticaria (Micropapular urticaria)Urticaria develops in response to a rise in the core body temperature within 2-30 minutes. The lesion lasts for 20- 90 minutesIt is associated with cholinergic sympathetic fibres.They are provoked bygeneralized heatingExerciseEmotional stressHot foodLocalized Heat urticariaVery rare type of urticaria that is seen after application of local heatLesions appear within 2-5 minutes of contact and lasts for about an hour.They can be provoked by applying a test tube full of water at 40degC to the forearm for five minutes.Solar urticariaUrticaria developing within 1-30 minutes of exposure to sunlightThey disappear within 24 hoursLesions are usually seen on the 'V' area of the neck and the arms.Solar urticaria may be the presenting sign in-Porphyria cutanea tardaSystemic lupus erythematosisErythropoietic protoporphyriaCold urticariaIt is of two types:IdiopathicSecondaryIdiopathic cold urticariaProbably transmitted as an autosomal dominant trait. Symptoms appear soon after birth and may persist life longUrticaria occurs in response to drop in the body temperature precipitated by generalized environmental rather than local cooling.Symptoms appear within 1/2 - 3 hrs of exposureAcquired or secondary cold urticaria-Urticaria precipitated by cold contact be it cold water, cold air, cold drinks or eatables.Condition is more common in young adults.Contact urticaria-Urticaria at the site of contactCommonly found on the hands or around the mouthAgents responsible are -FoodFood additivesDrugsSalivaGrassPollenAlso know:Drugs precipitating urticariaPenicillin (60%)Sulfonamides (15 %)Aspirin (15%)Chloramphenicol (5%)Phenytoin (5%)Difference b/w Urticaria and AngioedemaAngioedema is frequently associated with urticaria, but the two may occur independently. Angioedema is a reaction similar to urticaria except that it occurs in deeper tissues and is clinically characterized by asymmetric swelling of tissues.Difference b/w Acute and chronic urticariaAcute urticaria persists for < 6 weeksChronic urticaria lasts for more than 6-8 weeksPathogenesis of urticariaHistamine plays the key roleT/T of urticaria-In both acute and chronic urticaria antihistamines are the basic drugs. Drug mostly used is hydroxyzine.In acute urticaria with laryngopharyngeal edema 0.5 to 1 ml of epinephrine should be injected subcutaneously.