History The questions most likely to be helpful pertain to the following: Travel (suggesting possible parasite exposure) Allergies Drug use Use of herbal products and dietary supplements, including L - tryptophan Systemic symptoms (eg, fever, weight loss, myalgias, arthralgias, rashes, lymphadenopathy) Systemic symptoms suggest that a minor allergic or drug cause is less likely, and a detailed evaluation for an infectious, neoplastic, connective tissue, or other systemic disorder should be done.