What is the localized skin response to contact with an allergen that may blister?

The localized skin response to contact with an allergen that may blister is indeed contact dermatitis. This condition occurs when the skin becomes inflamed after being exposed to an irritant or an allergen causing an immune response. The hallmark of contact dermatitis includes redness, swelling, and the development of blisters, which occurs due to the body's hypersensitivity to the substance that triggered the reaction.

Contact dermatitis can manifest in various forms, such as irritant contact dermatitis, which is a reaction to non-allergic substances, and allergic contact dermatitis, which is an immune response to allergens. Both types share similar symptoms, making this response particularly relevant in the context of skin allergies.

In contrast, the other options refer to different skin conditions that do not primarily result from allergen exposure in the same manner as contact dermatitis. Folliculitis is an inflammation of hair follicles usually caused by infection and does not specifically represent an allergic response. Impetigo is primarily a bacterial infection characterized by pustules and crusting, while dermatitis herpetiformis is related to gluten sensitivity and presents with itchy, blistering skin but is distinctly different from contact dermatitis in its causative factors.