A 21-year-old female presented with complaints of new-onset asymptomatic, erythematous plaques localized to the tattooed sites on her body. The patient had a history of psoriasis for the past three years. She initially had psoriatic plaques with a typical morphology in a generalized distribution present on the normal (nontattooed) skin which had resolved around three months ago. Around two months ago, she started developing erythematous plaques with minimal scaling localized to the tattooed sites. History revealed that the patient had gotten these tattoos two years ago. She did not recall any history of flare in psoriasis at the time of tattooing. Examination showed erythematous plaques localized to some areas of tattooed skin over the right forearm, leg, and left breast Figure 1a-c. Clinically, differential diagnoses considered were late-onset psoriatic koebnerization, granulomatous reaction secondary to tattoo ink, lichenoid tattoo reaction, and tattoo sarcoidosis.Figure 1: Cutaneous examination revealed decorative black ink tattoos with overlying erythematous plaques bearing fine whitish scales sharply confined to the tattooed areas over the right forearm (a), right leg (b), and left breast (c)Biopsy revealed a normal epidermis with dermal lymphohistiocytic infiltrate forming noncaseating granulomas with deposition of red pigment Figure 2a and b.Figure 2: (a and b) Hist opathological examination of the affected area showed a normal epidermis with dermis displaying focal aggregates of lymphocytes, epithelioid histiocytes, and foreign body giant cells containing red tattoo pigment, findings consistent with foreign body granuloma (H and E, 40×) (a) and (H and E, 200×) (b). H and E = Hematoxylin and EosinANSWER: Granulomatous reaction secondary to tattoo ink Tattooing for cosmetic purposes has gained popularity in recent times. Cutaneous reactions to tattoos have generally been attributed to metallic salts used in the preparation of the pigment. Commonly reported reactions to tattoos can be divided into infections, allergic contact dermatitis to tattoo pigment, granulomatous reactions, lichenoid tattoo reaction, and localization of inflammatory skin conditions like psoriasis and eczema on the tattoo area.1 Rarely, cutaneous skin conditions like pseudolymphomatous reactions and keratoacanthomas may develop. There have been a few case reports of exogenous pigments in the tattoo, inducing a sarcoidal granulomatous reaction presenting as a localized cutaneous disease or heralding systemic involvement.2 Evolution of erythematous papules to scaly plaques localized to tattoo sites, presenting months to years after tattooing should raise suspicion of lichenoid reaction to tattoo, granulomatous reactions, and sarcoidal reactions.3 These can be differentiated on the basis of histopathology. Multiple case reports of psoriasis showing isomorphic response localized to the tattoo sites with a delay of weeks to years after the tattooing process have also been reported. Most of these patients had a previous history of psoriasis, while a few were diagnosed with psoriasis after the appearance of koebnerization over tattoo sites.4 Table 1 summarizes the clinical differentials in the above case along with the expected histopathological findings. Since our patient had a previous history of psoriasis, we had also kept the differential of late-onset koebnerization. However, there were no classical findings of psoriasis on histopathology. There was significant improvement within 4 weeks with topical mometasone furoate 0.1% cream. Steroids, laser therapy, and surgical excision have been considered in patients presenting with such tattoo.Table 1: Summarizes the clinical differentials in the above case along with the expected histopathological findingsIn suspected cases, especially in front of papulonodular lesions arising from a tattoo, it is important to perform an early diagnosis through histopathology. Key learning points Delayed Granulomatous Reactions to Tattoo PigmentsTattoo ink can incite granulomatous inflammation, often with noncaseating granulomas containing pigmentladen histiocytes—typically appearing months to years after tattooing. These reactions can mimic sarcoidosis and pose diagnostic challenges.Koebner Phenomenon in Psoriasis within TattoosIn individuals with psoriasis, Koebnerization can manifest at tattoo sites—even years after the procedure—resulting in psoriatic lesions localized to those areas.Therapeutic Approaches and Avoidance of Ink Dispersion InterventionsManagement often includes topical or systemic corticosteroids and, in some cases, antimalarials (e.g., hydroxychloroquine). Declaration of patient consent The authors certify that they have obtained all appropriate patient consent. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.
Herlekar et al. (Thu,) studied this question.