Which preparations form the mainstay of psoriasis treatment?

Correct Answer: B

Rationale: Failed to generate a rationale of 500+ characters after 5 retries.

Correct Answer: D

Rationale: The correct answer is D because nails are indeed useful for scratching, protecting the ends of fingers and toes, and picking up small objects. Nails have various functions due to their structure and strength. They can be used to scratch an itch, provide protection to the fingertips and toes, and aid in picking up small items. Therefore, D is the correct choice as it encompasses all the valid uses of nails. Choices A, B, and C are incorrect individually as they only represent specific functions of nails, whereas option D covers all the mentioned uses.

Correct Answer: A

Rationale: The correct answer is A: keratin. Keratin is a structural protein found in the epidermis that forms a protective barrier to prevent dehydration. It helps to waterproof the skin and protect it from environmental factors. Melanin (B) is responsible for skin pigmentation, collagen (C) provides structural support, and elastin (D) helps skin elasticity. However, these proteins do not specifically prevent dehydration in the epidermis.

Correct Answer: C

Rationale: The correct answer is C because elastin is not present in the epidermis but in the dermis. Elastin gives skin its elasticity, not in the epidermis but in the dermis. The epidermis mainly consists of keratinocytes. Therefore, the statement that Elastin in the epidermis loses its elasticity with age is incorrect. Choices A, B, and D are all true statements about the proteins of the skin. Melanin production being genetic, keratin in nails being stronger than in the stratum corneum, and collagen fibers in the dermis providing strength are all accurate characteristics of skin proteins.

Correct Answer: B

Rationale: The correct answer is B, harsh soaps. Harsh soaps contain chemicals that can strip the skin of its natural oils, leading to skin irritation in individuals with irritant-type contact dermatitis. Warm water (choice A) is not a common irritant unless it is too hot. Nonlatex gloves (choice C) are typically used to protect the skin and are less likely to cause irritation. Vegetable oils (choice D) are generally considered safe and may even provide moisture to the skin.