This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Dermatitis Erythema, Subject name: Skin
Chronic urticaria is a - 
Select and explain. 
A. Type 1 hypersensitivity reaction, B. Type 2 hypersensitivity reaction, C. Type 3 hypersensitivity reaction, D. Type 4 hypersensitivity reaction
A: Type 1 hypersensitivity reaction
Answer: A: Type 1 hypersensitivity reaction 
Explanation: Ans. is 'a' i.e., Type 1 hypersensitivity reaction Types of hypersensitivity reactionType of hypersensitivity reactionExamplesMediatorsType 1 (immediate type)Atopic dermatitisUrticariaAnaphylaxisInsect bite hypersensitivityAllergic rhinitis and asthmaIgEType 2 (cytotoxic, antibody dependent)Autoimmune hemolytic anemiaRheumatic heart diseaseThrombocytopeniaErythroblastosis foetalisGoodpasture's syndromeGrave's diseaseMyasthenia gravisIgG or IgMMACComplementType 3 (immune complex disease)Serum sicknessArthus reactionRheumatoid arthritisPost streptococcal glomerulonephritisMembranous nephropathyLupus nephritisSystemic lupus erythematosusExtrinsic allergic alveolitis(hypersensitivity pneumonitis)Generalized drug eruptionErythema multiformeErythema nodosumTENIgGComplementNeutrophillsType 4 (delayed type)TuberculosisLeprosyContact dermatitisChronic transplant rejectionMultiple sclerosisT-cells