Reações aos diferentes pigmentos de tatuagens: relato de dois casos / Reactions to the different pigments in tattoos: a report of two cases

A tatuagem é definida como deposição de pigmento intencional ou acidental na pele. Os pigmentos têm sido associados a diversas dermatoses, como a dermatite de contato alérgica, a dermatite liquenoide e as reações fotoinduzidas, granulomatosas, sarcoídeas e pseudolinfomatosas. Enfocam-se os diversos tipos de reações aos pigmentos e a importância de reconhecê-los clinicamente. São relatados dois casos: um de dermatite liquenoide sobre o pigmento vermelho e outro de pseudolinfoma sobre os pigmentos vermelho e lilás e de reação fotoinduzida sobre o amarelo. A remoção geralmente requer múltiplos tratamentos, e a maioria não retira as cores completamente.

Tattoos are defined as the intentional or accidental deposit of pigment into the skin. These pigments have been associated with various dermatoses such as allergic contact dermatitis, lichenoid dermatitis, photoinduced reactions, and granulomatous, sarcoid and pseudolymphomatous reactions. The objective of this report was to describe the various types of reactions to pigments and the importance of recognizing them clinically. Two cases are reported: one of lichenoid dermatitis resulting from a reaction to the red pigment of a tattoo and the other of a pseudolymphoma resulting from a reaction to red and lilac pigments and a photo-induced reaction to a yellow pigment. Removal generally requires multiple forms of treatment, most of which fail to remove the colors completely.

Transmission electron microscopy of the preclinical phase of experimental phytophotodermatitis

OBJECTIVE: To examine the epidermis in induced phytophotodermatitis using transmission electron microscopy in order to detect histologic changes even before lesions are visible by light microscopy. INTRODUCTION: In the first six hours after the experimental induction of phytophotodermatitis, no changes are detectable by light microscopy. Only after 24 hours can keratinocyte necrosis and epidermal vacuolization be detected histologically, and blisters form by 48 hours. METHODS: The dorsum of four adult rats (Rattus norvegicus) was manually epilated. After painting the right half of the rat with the peel juice of Tahiti lemon, they were exposed to sunlight for eight minutes under general anesthesia. The left side was used as the control and exposed to sunlight only. Biopsies were performed immediately after photoinduction and one and two hours later, and the tissue was analyzed by transmission electron microscopy. RESULTS: No histological changes were seen on the control side. Immediately after induction, vacuolization in keratinocytes was observed. After one hour, desmosomal changes were also observed in addition to vacuolization. Keratin filaments were not attached to the desmosomal plaque. Free desmosomes and membrane ruptures were also seen. At two hours after induction, similar changes were found, and granular degeneration of keratin was also observed. DISCUSSION: The interaction of sunlight and psoralens generates a photoproduct that damages keratinocyte proteins, leading to keratinocyte necrosis and blister formation. CONCLUSIONS: Transmission electron microscopy can detect vacuolization, lesions of the membrane, and desmosomes in the first two hours after experimental induction of phytophotodermatitis.