Air-borne contact dermatitis can be diagnosed by:

Ans: B (Patch test) Ref: Eczema. In: Thappa DM. editor. Essentials in Dermatology, 2nd,edn.. New Delhi: jaypee brothers medical publishers (P) Ltd 2009:99-113. & Atopic dermatitis. Eczema and non infectious immunodeficiency disorders. In: James WD. Berger TG, Elston DM. editors. Andrew's diseases of the skin: Clinical Dermatology, 11th edn., China: Saunders Elsevier 2011: 62-87.Explanation:Patch test - Application of allergens suspected to be the cause of allergic contact dennatitis to intact uninflamed skin in non irritating concentrationDiagnostic of allergic contact dermatitis (airborne contact dermatitis is a type of allergic contact dermatitis wherein the allergens are airborne like pollen, cement, etc)Patch test - Delayed hypersensitivity (type IV hypersensitivity)Reading done two days laterPrick testType I hypersensitivity reaction, used to detect allergy to a host of allergens like food, dust, insects, drugs, etcDone in atopic dermatitis, chronic urticaria, allergic rhinoconjunctivitis, bronchial asthmaReading done in 15 minutesSerum IgE levels are non specifically elevated in allergic conditions characteristically high levels are seen in atopic dermatitis and very high levels in hyper IgE syndromeSkin biopsy reveals nonspecific features of spongiosis seen in all cases of dermatitis and not specific for airborne contact dermatitis.