Rapid-Onset Unilateral Papular Granuloma Annulare-like Granulomatous Reaction After a Mesotherapy-like Cosmetic Procedure

Mesotherapy and related cosmetic microinjection or microneedling procedures are increasingly used for aesthetic indications. However, their safety profile is difficult to define because injectates, devices, injection depths, and treatment protocols vary widely. We report a case of rapid-onset papular granuloma annulare (GA)-like granulomatous reaction after a mesotherapy-like cosmetic procedure. An Asian woman in her forties developed multiple 2–3 mm erythematous papules in a regular grid-like distribution corresponding to facial injection sites. Papules were limited to the left hemiface despite bilateral treatment with the same sodium hyaluronate-containing skincare serum delivered using a suction-assisted 9-pin multi-needle mesogun. Histology showed necrobiotic granulomas with palisading epithelioid histiocytes and increased dermal mucin. After nine sessions of intralesional triamcinolone acetonide, near-complete clinical resolution was documented 14 months after the first intralesional triamcinolone session. This case highlights an unusual rapid-onset, papular, grid-patterned GA-like granulomatous reaction after a mesotherapy-like cosmetic procedure. The temporal and anatomical relationship to injection supports a procedure-associated reaction. Potential contributors include injected materials, use of products not intended for injection, suction-assisted multi-needle delivery, altered injection pressure or depth, repeated passes, mechanical trauma or Koebnerisation, delayed-type hypersensitivity, foreign-body response, contamination, and host susceptibility. This case does not establish a causative agent or reproducible procedure-specific adverse reaction, but documents a distinctive rapid-onset, grid-like papular GA-like reaction after poorly characterized cosmetic interventions.