A 11-year-old female admitted to our hospital because of erythema of the face and the trunk, and a wide and dense cluster of verruca vulgaris on the right sole. She had no family history of immunodeficiency, no perinatal abnormality, no growth abnormality, or no history of severe infections. From the age of 4 years, she noticed erythema around her nose. At the age of 9 years, small erythema and papules appeared on her chest. In January, 2003, erythema around her nose and papules of the trunk spread rapidly, and she also felt fatigue and effort dyspnea. Laboratory examinations revealed near absence of serum IgG, and IgE, high serum IgM (525 mg/dl), and normal IgA and IgD. Thl/Th2 ratio was 36.9. We diagnosed her as having hyper-IgM syndrome. Histological examinations of a skin biopsy showed the infiltration composed of mainly histiocytes,and mildly atypical CD8 + T cells around the blood vessels in the dermis. We concluded her skin manifestations as reactive lymphohistiocytic infiltration at the base of immunodeficiency and durable stimulation of various antigens. Her skin manifestations improved transiently by the intravenous immunogrobulin and corticosteroids therapy.