healthy-appearing female in no acute distress

Case 2

Chief Complaint
(CC)  

A 45-year-old female presents with a complaint of an itchy red rash on her arms and legs for about two weeks. 

Subjective

She has been going on a daily basis to the local YMCA with children for Summer camp.

Objective Data

VS

(T) 98.3°F; (RR) 18; (HR) 70, regular; (BP) 118/74

General

healthy-appearing female in no acute distress

HEENT

EYES: no injection, no increase in lacrimation or purulent drainage;
EARS: normal
TM: Normal 

Skin

CTA AP&L

Neck/Throat

mild edema with inflammation located on forearms, upper arms, and chest wall, thighs and knees; primary lesions are a macular papular rash with secondary linear excoriations on forearms and legs 

1. What other subjective data would you obtain?

2. What other objective findings would you look for?

3. What diagnostic exams do you want to order?

4. Name 3 differential diagnoses based on this patient presenting symptoms?

5. Give rationales for your each differential diagnosis.