Cutaneous T-cell lymphoma (CTCL) patients are frequently accompanied by sever pruritus. They may suffer from infection caused by hard scratching pruritus skin, resulted in sepsis. Management of strong itch is important for treatment of CTCL. CTCL and atopic dermatitis (AD) shares common aspects of clinical appearance. Previous paper reported that some pruritus factors in AD were also found in mycosis fungoides (MF) and Sézary syndrome. However, detail of pruritus mechanism in MF is still unknown.
 To explore the mechanism of itch in MF, we analyzed representative pruritus factors, which were known in AD. Finally, we analyzed correlation of itch score with each factor and compared level of each factor between in early and progressive stages.    
 Samples from 22 cases with MF (mean age 62, age range 26-89, gender ratio Male:Female=7:4) were collected in this study. Clinical data, serum samples, and tissue samples were analyzed by biochemical and pathological approach. Serum levels of eosinophils, LDH, IgE, IL-5, beta-NGF, IL-31, TARC, sIL-2R and autotaxin were analyzed by Enzyme-Linked ImmunoSorbent Assay. Pruritus was analyzed using VAS itch score (0-100). Tissue specimens were stained with TSLP in epidermis.
Itch VAS score was correlated with serum level of eosinophils, IL-5, IL-31, TARC and sIL-2R significantly. Serum NGF level was not correlated with VAS itch score in MF. Eosinophils, sIL-2R and TARC showed significance between patch/plaque stage and tumor/advanced stage. IL-31 also increased more in advanced stage than in early stage (p=0.056). On the other hand, autotaxin didn’t show significant correlation with VAS itch score or tumor stage. In histological analysis, TSLP was also detected in epidermis of MF, compared with normal skin.
Our result implied that itch of MF might be caused by eosinophils and Th2 related factor. There was possibility that proliferative MF cells, which expressed CCR4 (receptor of TARC), had an important role of pruritus for the center of pruritus mechanism. It seemed difficult to distinguish diagnosis of MF from AD by pruritogens, but developed new treatment of itch in AD patients may help management of treatment in MF patients.

Histopathological findings of MF mimic that of atopic dermatitis, and show infiltration of lymphocytes into epidermis and eosinophils in dermis. Increased serum concentration of IL-31 was also found in MF patients. 
MF and AD shared the many aspects of mechanism in pruritus.

Analysis of pruritous factor in cutaneous T cell lymphoma