A 61-year-old man presented with recurrent folliculitis-like eruptions of the skin. His history was significant for a prior history of infection of the cheek with methicillin-resistant Staphylococcus aureus (MRSA) treated with minocycline. Six years earlier, he had suffered infection of a pacemaker site with MRSA, which had spread to his upper extremities, but was ultimately controlled with antibiotics. He denied intravenous drug use. Physical examination revealed a 1-cm indurated nodule over his left cheek, a 5 × 3 cm hyperpigmented patch over his left ankle, and scattered areas of erythema over his anterior chest wall and dorsum of his legs. MBL level was < 50 ng/ml, while all classes of immunoglobulins were within normal range (Table ). MBL genotyping revealed the LYPB/HYPD haplotypes. MASP-2 genotype was the wild type (A/A). MBL functional pathway test was impaired (Table ). A skin biopsy of the folliculitis-like rash (Figure ) was performed, revealing Grover's disease (transient acantholytic dermatosis). Topical therapy was instituted with triamcinolone.
A 39-year-old woman complained of recurrent pustular eruption of her upper extremities and chronic allergic rhinitis. Immunological evaluation demonstrated the following: IgG levels were slightly decreased, but IgG subclass levels were all normal. The patient had detectable/robust responses to 6/14 pneumococcal serotypes (Table ). Further work-up yielded a low level of MBL at < 50 ng/ml (reference: >100 ng/ml), as well as an impaired MBL pathway functional test using the C4b deposition assay. Genotyping showed the HYPD/HYPD variant of MBL2 and wild-type MASP-2 genotype (A/A) (Table ).