A 10-year-old child presents to the school nurse with complaints of an itchy rash on the right arm.
Based on these findings, identify the medical term of this rash, and what would be the common topical treatment drug class.

Choice A rationale

For scabies treatment with topical permethrin in children, the medication should be applied from the neck down to the toes, ensuring all skin surfaces are covered because scabies mites can burrow anywhere on the body. The permethrin should be left on for the prescribed duration, typically 8-14 hours or overnight, to allow sufficient contact time to kill the mites and their eggs.

Choice B rationale

Applying permethrin only to affected areas may not be sufficient to eradicate scabies because mites can be present on areas of the skin that do not yet show visible signs of infestation or itching. Complete coverage is necessary to ensure treatment success.

Choice C rationale

Applying permethrin only to the scalp is inadequate for treating scabies, as the mites commonly infest other areas of the body. While scabies can affect the scalp, especially in infants and young children, treatment must extend to all skin surfaces from the neck down.

Choice D rationale

A hot bath should be avoided before applying permethrin. Hot water can irritate the skin and increase absorption of the medication, potentially leading to systemic toxicity or reduced effectiveness. Permethrin is typically applied to cool, dry skin.

Choice A rationale

A tick is the arachnid responsible for transmitting Lyme disease. The characteristic rash associated with Lyme disease is erythema migrans, often described as a "bull's-eye" rash, which can appear days to weeks after a bite from an infected blacklegged tick (Ixodes scapularis or Ixodes pacificus). Spending time in wooded areas increases the risk of tick exposure.

Choice B rationale

Spiders are arachnids, but they are not the primary vector for Rocky Mountain spotted fever. Rocky Mountain spotted fever is caused by the bacterium Rickettsia rickettsii and is transmitted to humans through the bite of infected American dog ticks (Dermacentor variabilis) or Rocky Mountain wood ticks (Dermacentor andersoni). The rash associated with this disease typically starts on the wrists and ankles and spreads centrally.

Choice C rationale

Mites are arachnids, and certain types cause scabies, a contagious skin infestation characterized by intense itching and a pimple-like rash due to the burrowing of the Sarcoptes scabiei mite into the skin. While hiking in wooded areas could potentially lead to exposure to some types of mites, the rash of scabies has a distinct presentation and transmission pattern different from Lyme disease.

Choice D rationale

Chiggers are also mites (arachnids) that can be found in wooded areas. Their bites cause chigger dermatitis, characterized by intensely itchy red welts or bumps where the larvae have attached to the skin. While the history of hiking is relevant to potential exposure to chiggers, the rash and the associated disease are distinct from the erythema migrans rash of Lyme disease. .