Correct Answer: C

Rationale: The correct answer is C. Contact with the grandson's new dog could have introduced new allergens or irritants, exacerbating the eczema symptoms. Choice A is unrelated to the exacerbation of symptoms. Choice B, receiving an influenza immunization, is unlikely to directly cause an exacerbation of eczema symptoms. Choice D, applying corticosteroid cream, is a common treatment for eczema and would not likely be the cause of the exacerbation.

Correct Answer: B

Rationale: In acute epiglottitis, the infected epiglottis becomes inflamed and can lead to sudden airway obstruction, which is a life-threatening emergency. This can cause difficulty breathing and necessitates immediate intervention to secure the airway. Increased carbon dioxide levels may occur due to inadequate ventilation resulting from airway obstruction, but the primary concern is the obstruction itself, not the carbon dioxide levels. Inability to swallow may be present due to pain and swelling in the throat but is not the immediate life-threatening complication associated with acute epiglottitis. Bronchial collapse is not a typical consequence of acute epiglottitis.

Correct Answer: B

Rationale: The correct answer is B: Weekly. Treatment of talipes involves manipulation and applying short leg casts. The casts need to be changed weekly to allow for further manipulation and to accommodate the rapid growth of the infant. Changing the casts daily (choice A) would be too frequent and may not provide enough time for the correction to take place. Changing the casts biweekly (choice C) or monthly (choice D) would not provide adequate support for the ongoing correction process required for talipes.

Correct Answer: B

Rationale: Type IV hypersensitivity reactions are mediated by T cells and cytokine release, leading to delayed reactions, unlike types I, II, and III, which involve antibodies. Choice A is incorrect because type IV reactions do not involve antigen-antibody complexes. Choice C is incorrect as type IV reactions do not result in immediate allergic reactions. Choice D is incorrect as type IV reactions are not the least severe form of hypersensitivity; in fact, they are known to cause significant tissue damage and inflammation.

Correct Answer: A

Rationale: The correct answer is High-density lipoprotein (HDL). HDL is known as 'good' cholesterol because it helps remove cholesterol from the arteries, reducing the risk of atherosclerosis. LDL (choice B) is considered 'bad' cholesterol as it can deposit cholesterol in the arteries, increasing the risk of atherosclerosis. VLDL (choice C) and IDL (choice D) are also associated with increased risk of atherosclerosis rather than decreasing it.