A 29-year-old female with no past medical history presented with a diffuse, itchy, erythematous papular rash . The rash was most severe on her anterior and posterior lower extremities bilaterally, and less prominent on her lower abdomen and lower forearms. The rash started 2 days prior to her visit and got progressively worse over that time. She felt well otherwise. She reported no new lotions, detergents, or clothes. She got a flu shot 2 days prior (which she had received in the past without incident and she denied an egg allergy), otherwise there were no new medications. The rash started later in the afternoon after she got her flu shot. The rash on her hands worsened with contact with hot water. She had taken 50 mg of benadryl the day before and the day of the visit, and the rash continued to progress and to become more itchy.

Vitals were normal. On exam, there was a diffuse, papular, erythematous blanchable rash on her anterior and posterior thighs, lower legs, and ankles bilaterally. Hypopigmentation surrounded the erythematous papules. The rash was less severe but similar in appearance on her lower abdomen and bilateral forearms and hands. There was one 3 cm × 3 cm erythematous wheal on the patient’s right medial ankle area.

The patient was treated for hives or a possible allergic reaction (to an unknown allergen). She was put on a 15-day prednisone taper (80 mg for 3 days, 60 mg for 3 days, 40 mg for 3 days, 20 mg for 3 days, 10 mg for 3 days).