an 81-year - old woman recognized pruritic scaly erythemas on the scalp 2 months before the visit to our hospital .
her medical history included nephrosis syndrome that had been treated with oral cyclosporine 100 mg / day for 8 years .
the results of routine blood work before the onset of skin eruptions had been normal .
although the head erythemas appeared to be seborrheic dermatitis ( sd ) , the lesions did not respond to topical steroidal lotion .
when she visited our hospital , the eruption had disseminated to the trunk and extremities , resulting in generalized erythroderma ( fig .
laboratory tests showed white blood cells 13,900/l ( normal 3,5009,800 ) , hemoglobin 11.9 mg / dl ( normal 11.315.5 ) , platelets 271,000/l ( normal 155,000365,000 ) , eosinophils 19.0% , atypical lymphocytes 2.0% , lactate dehydrogenase 517
iu / l ( normal 176353 ) and soluble interleukin-2 receptor 1,510 u / ml ( normal < 550 ) ; human t - lymphotropic virus type i antibody was negative .
a skin biopsy of the erythema of the trunk showed that lymphocytes and eosinophils had infiltrated dominantly to the superficial perivascular space .
2 ) . polymerase chain reaction and flow cytometry of the skin specimens failed to detect malignant cells .
however , atypical lymphocytes ( basket cells ) were detected in the peripheral blood and bone marrow ( fig .
3 ) . flow cytometry of the blood and bone marrow specimens showed that malignant cells were positive for cd2 , cd3 , cd4 , cd5 , cd7 , cd25 and cd45ra .
positron emission tomography - computed tomography revealed abnormal enhancement of axillary and inguinal lymph nodes and bone marrow .
we consulted a hematologist and peripheral t cell lymphoma not otherwise specified ( ptcl - nos ) , stage iv according to ann arbor   was diagnosed .
ptcl can cause sd - like dermatitis that gradually develops into auto - sensitization dermatitis . as chemotherapy was dismissed considering her age , we administered fexofenadine 120 mg / day and oral prednisolone 20 mg / day so as to alleviate erythroderma and pruritus .
we added pregabalin 50 mg / day according to the recommendation by yosipovitch , which reduced pruritus dramatically .
the amount of daily oral steroid was tapered to 5 mg over 4 months , maintaining remission of cutaneous symptoms .
few publications have described sd as a paraneoplastic syndrome in cases with lung cancer and lymphoma [ 4 , 5 , 6 ] .
the diagnosis of paraneoplastic syndrome usually requires concurrent onset and parallel course with malignancy at least .
although we could not confirm whether the severity of the sd would parallel that of ptcl , sd seems to be a paraneoplasia since the onset of the sd coincided with that of ptcl and the sd was resistant to ordinary topical therapy .
although the mechanisms of pruritus as well as the antipruritic effect of anticonvulsive agents are not clear , they probably inhibit central itch pathways .
in this case , simple sd and subsequent auto - sensitization dermatitis were suspected at first . however , the sd was too resistant to ordinal therapy and developed to erythroderma .
complete blood count revealed the presence of lymphoma that became an important clue to diagnosis .
 seborrheic dermatitis is an inflammatory eruption that tends to distribute on the sebaceous areas of the body and is rarely described as a paraneoplasia . here 
 we report a case with a responsive seborrheic dermatitis - like eruption of the head which resulted in generalized erythroderma . 
 intensive examinations detected concurrent malignant lymphoma . 
Case Report
Discussion
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