PEEPO: papular eruption with elimination of papillary oedema

Multiple biopsies from a patient with a pruritic papular eruption of endogenous origin demonstrated a sequence of histopathological changes which varied markedly with the age of the lesion. Early lesions showed marked papillary oedema but no evidence of epidermal involvement. The next phase was characterized by the appearance of focal spongiosis and intra-epidermal vesiculation without involvement of the stratum corneum. Late lesions were characterized by residual spongiosis in the epidermis and groups of pyknotic nuclei in a parakeratotic stratum corneum. It would seem that this sequence of events is due to the elimination of papillary oedema through the epidermis. The fact that this process produces changes indistinguishable from those seen in eczema may indicate the eczema itself is a condition characterized by sub-epidermal oedema in which the epidermis is involved only as a secondary event. The title TEEPO (trans-epidermal elimination of papillary oedema) is suggested as a suitable acronym for this phenomenon. The term PEEPO (papular eruption with elimination of papillary oedema) is proposed for the eruption seen in this patient.