Rheumatologic and Immunologic Manifestations of Epidermolytic Hyperkeratosis: A Special Case Description and Literature Review

We present a 57-year-old male with a lifelong history of Epidermolytic Hyperkeratosis (EH) who developed severe symmetrical polyarthritis with deformities resembling Rheumatoid Arthritis (RA).Methotrexate therapy yielded significant improvement in both articular and cutaneous manifestations.This case highlights the rare association between EH and inflammatory arthritis and underscores the potential role of systemic immunosuppression in managing such patients.Discussion: While EH primarily affects the skin, this case illustrates a rare inflammatory arthritis phenotype mimicking seronegative RA.The robust response to methotrexate suggests shared inflammatory pathways (e.g., IL-17/IL-23 upregulation in EH and psoriatic arthritis).Further studies are needed to explore this association.Conclusion: Methotrexate may be effective for EH-associated polyarthritis.Early rheumatologic referral is recommended for EH patients with articular symptoms.