When ink triggers inflammation: A case of tattoo granuloma confined to red pigment

Tattoo granulomas are chronic inflammatory reactions to exogenous pigments, most frequently involving red ink due to its higher antigenic potential.^1,2 We report a localised granulomatous reaction confined exclusively to red pigment and discuss the cautious use of Q-switched neodymium-doped yttrium aluminum garnet (Nd:YAG) laser therapy.

A 26-year-old woman presented with mildly pruritic indurated nodules confined to the red pigment of a tattoo placed 3 years earlier; lesions developed 1 year after tattooing. There was no history of atopy, sarcoidosis, or prior treatment. Clinical examination revealed erythematous, firm papules and nodules strictly confined to red-pigmented segments. Other colored areas were uninvolved [Figure 1]. Dermoscopy (10× polarised) demonstrated structureless pink–reddish areas, whitish scar-like zones, and irregular blue–gray pigmentation [Figure 2]. Histopathology revealed lymphohistiocytic infiltrate with ill-formed granulomas, multinucleated giant cells, and intra- and extracellular red pigment deposits, consistent with a foreign body granulomatous reaction [Figure 3].

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Figure 1:

A 26-year-old female with a tattoo granuloma showing well-defined, indurated nodules and plaques strictly limited to the red pigment areas of the tattoo over the flexor aspect of the right forearm.

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Figure 2:

Dermoscopic image (ILLUCO IDS-1100, Polarized, 10x) showing a structureless pattern characterized by pink to reddish areas, whitish scar-like zones, and irregular blue-gray pigmentation. (ILLUCO IDS-1100 is the model name of the dermoscope used).

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Figure 3:

Histopathology showing: (a) Dense dermal infiltrate with predominant lymphohistiocytic and ill-formed granuloma (red arrows, hematoxylin and eosin (H&E), 10x), (b) Foci of giant cell reaction (yellow arrows, H&E, 40x) (c) Intracellular and extracellular pigment deposits (red circle, H&E, ×40).

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Special stains for acid–fast bacilli (Ziehl–Neelsen), periodic acid–Schiff, and Fite were not performed. Based on clinicopathological correlation – including strict confinement to red pigment, absence of systemic features, lack of necrosis, and classic foreign body granulomatous morphology – infectious etiologies were considered unlikely.

Differential diagnoses, including allergic contact dermatitis, lichenoid tattoo reaction, pseudolymphoma, sarcoidosis, and infection, were excluded clinically and histologically.^1,2

Treatment was performed using a Q-switched Nd:YAG laser (532 nm), the standard wavelength targeting red tattoo pigment. Parameters included 2.0–2.5 J/cm² fluence, 3 mm spot size, 6 ns pulse duration, and 2 Hz repetition rate, delivered in a single pass to an immediate frosting endpoint. Two sessions were performed 4 weeks apart with contact cooling and without anesthesia. Intralesional triamcinolone acetonide was administered between sessions to reduce inflammation.

The rationale for Q-switched Nd:YAG laser use in granulomatous tattoo reactions lies in selective photomechanical fragmentation of pigment particles, potentially reducing dermal antigen load and facilitating macrophage-mediated clearance.^3-5 Case-based reports describe improvement in localized granulomatous reactions following pigment-targeting laser therapy.^3,4

However, laser therapy in immune-mediated tattoo reactions remains controversial. Pigment fragmentation may increase antigen exposure and exacerbate inflammatory responses. Reports of inflammatory flares following laser treatment underscore the need for careful patient selection.^4,6 Therefore, laser use requires a balanced risk–benefit assessment, particularly when lesions are localized, and infection has been reasonably excluded.

In our case, clinical improvement was observed without recurrence at 4-week follow-up after the final session [Figure 4]. Importantly, this short follow-up precludes conclusions regarding long-term durability or definitive clearance.

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Figure 4:

Follow-up image after 2 sessions of Nd:YAG laser therapy (532 nm) showing red pigment clearance and reduction in induration.

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In addition, intralesional triamcinolone represents a significant confounder, as corticosteroid-induced immunomodulation may have contributed to lesion regression independent of laser-mediated pigment reduction. Thus, the relative contribution of the Q-switched Nd: YAG laser cannot be determined with certainty.

This case highlights:

• Selective red pigment involvement in granulomatous tattoo reactions

• Utility of dermoscopy as a non-invasive adjunct

• Essential role of histopathology for definitive diagnosis

• Need for cautious risk–benefit evaluation before laser intervention