In dermatology practice, patients frequently present with a recalcitrant eruption distinguished by the presence of edematous, urticarial, intensely pruritic papules. After analysis of patient biopsy specimens, the dermatopathologist will often report a “dermal hypersensitivity reaction” (DHR) characterized by an eosinophil-rich infiltrate. The only clinical differentials that correspond to this pathologic diagnosis are arthropod bite and drug eruption, neither of which is clinically relevant to the present case.
Flugman SL. Long-term Control of Papular Dermatitis (“Dermal Hypersensitivity Reaction”) With Mycophenolate Mofetil. Arch Dermatol. 2006;142(11):1508-1518. doi:10.1001/archderm.142.11.1512