AUTHOR=Kondo Shumpei , Yunoki Marina , Otsuka Masaki , Tokura Yoshiki 

TITLE=Case report: Reactive granulomatous dermatitis presenting with inguinal erythematous plaques in a patient administered with pravastatin

JOURNAL=Journal of Cutaneous Immunology and Allergy

VOLUME=Volume 7 - 2024

YEAR=2024

URL=https://www.frontierspartnerships.org/journals/journal-of-cutaneous-immunology-and-allergy/articles/10.3389/jcia.2024.13640

DOI=10.3389/jcia.2024.13640

ISSN=2574-4593

ABSTRACT=There has been an identical group of disorders coined the terms “interstitial granulomatous dermatitis” and “palisaded neutrophilic and granulomatous dermatitis”. In addition, a drug-induced subset of this condition was named “interstitial granulomatous drug reaction (IGDR)”. More recently, “reactive granulomatous dermatitis (RGD)” was proposed as an umbrella term encompassing these three disorders. A considerable number of RGD cases are associated with systemic conditions, including autoimmune diseases, such as rheumatoid arthritis and systemic lupus erythematosus, inflammatory bowel diseases, and malignancies. Drugs are another cause, as represented by IGDR. We present a case of a 74-year-old Japanese man showing an asymptomatic well-demarcated erythema eruption on bilateral inguinal region extending lower abdomen and proximal thigh area. He had hyperlipidemia and received pravastatin for 4 years. A biopsy specimen taken from the erythematous lesion revealed infiltration of lymphocytes and histiocytes in the upper to lower dermis. Interstitial infiltrates of histiocytes and lymphocytes were found as they were dispersed among collagen bundles. By immunostaining, CD68+ macrophages were intermingled with CD4+ and CD8+ T cells. Based on the clinical and histologic findings, the eruption was diagnosed as RGD. Because of the possibility of IGDR, the intake of pravastatin was ceased. His eruption completely disappeared within 6 months after the discontinuation. The list of drugs to cause RGD includes angiotensin converting enzyme inhibitors, antihistamines, β-blockers, antidepressants, and anticonvulsants, tocilizumab and ustekinumab. Meanwhile, various statins have been reported to induce drug eruptions. The eruption types are mainly eczematous or lichenoid reaction, or rarely psoriasiform or ichthyosiform. There was only one report documenting that RGD occurred in patients administered with rosuvastatin, showing annular, violaceous plaques distributed on the extremities, proximal trunk and intertriginous areas. Pravastatin induces lichenoid eruption, but RGD has not been documented. Our case suggests that RGD is underestimated as adverse effect of statins possibly because of its unusual skin manifestation.