psd-502 and Psoriasis

Eutectic mixture of 2.5% lidocaine and 2.5% prilocaine (EMLA AstraZeneca, DE) is a widely used topical anesthetic cream for preprocedural cutaneous analgesia. In addition to potential clinical cutaneous and systemic adverse effects, EMLA may also induce microscopic changes detectable by light and electron microscopy leading to difficulty in accurate diagnosis. We report the case of a biopsy demonstrating EMLA-induced histopathologic changes. The biopsy was taken from the back of a 5-month-old infant and submitted to rule out psoriasis. Hematoxylin and eosin (H&E) staining of the biopsy demonstrated spongiosis and a noninflammatory subepidermal bulla, raising the histopathologic possibility of epidermolysis bullosa. Further investigation confirmed that EMLA was applied under occlusion before biopsy. A second biopsy without topical anesthetic did not demonstrate a bulla and supported the clinical diagnosis of psoriasiform dermatitis. Our case highlights the importance of awareness of EMLA-induced histopathologic changes to avoid potential misdiagnosis. The histopathologic findings of this case in conjunction with other previously reported cases of EMLA-induced bullae were analyzed. Vacuolization of the basal and suprabasilar layer, pallor and swelling of upper layer epidermal keratinocytes, a pauci-inflammatory cleavage beneath or within the basal layer, basophilic granular karyorrhectic debris in the subepidermal cleft, and congestion of papillary dermal vessels characterized the biopsy findings of this localized adverse reaction.

Topics: Biopsy; Drug Eruptions; Female; Humans; Infant; Lidocaine; Lidocaine, Prilocaine Drug Combination; Prilocaine; Psoriasis; Skin Diseases, Vesiculobullous

A eutectic mixture of 5% lidocaine and prilocaine was applied under occlusion for 1 or 2 hours on 25-100 cm2 areas of normal and diseased skin, and the absorption was followed by measuring the concentrations of the drugs in the draining vein and the general circulation at different time intervals after the application. The analgesic and vascular effects in the skin were also recorded. When the mixture was applied on normal skin the absorption was more rapid from the face than from the forearm. The absorption from diseased skin was faster than that from normal skin, with higher plasma concentrations, and a more rapid but shorter anesthetic effect was noted. With the doses used the plasma levels in the general circulation were 100 times lower than those associated with toxicity. The drug concentrations in the draining vein were highest after treatment of diseased skin and were 2-90 times higher than in the general circulation. The plasma concentrations of lidocaine and prilocaine ran parallel to each other, but the prilocaine level was 10-50% lower than that of lidocaine in the draining vein and 200-300% lower in the general circulation.

Topics: Anesthetics, Local; Dermatitis, Atopic; Dermatitis, Contact; Drug Combinations; Face; Female; Forearm; Humans; Lidocaine; Lidocaine, Prilocaine Drug Combination; Male; Prilocaine; Psoriasis; Skin Absorption