ExplanationB. The first and most common clinical manifestation of acute GVHD is a maculopapular rash, usually occurring at or near the time of the white blood cell engraftment. The rash initially involves the nape of the neck, ears, shoulders, the palms of the hands, and the soles of the feet. It appears as a sunburn and may be pruritic or painful. In severe GVHD, the maculopapular rash forms bullous lesions with toxic epidermal necrolysis. Histologic examination of acute GVHD of the skin reveals changes in the dermal and epidermal layers. Characteristic findings include exocytosed lymphocytes, dyskeratotic epidermal keratinocytes, follicular involvement, satellite lymphocytes adjacent to or surrounding dyskeratotic epidermal keratinocytes, and dermal perivascular lymphocytic infiltration. The most consistent histologic feature is individual cell death (apoptosis) at the base of crypts. Skin GVHD is divided into four stages.
