Although Demodex mites do not seem to be the cause of rosacea, they may represent an important cofactor, especially in papulopustular rosacea. Immunohistochemical findings suggest that a delayed hypersensitivity reaction, possibly triggered by antigens of follicular origin, probably related to D. folliculorum, may occur, stimulating progression of the affection to the papulopustular stage.

Figure 1 Multiple, depigmented macules under the henna tattoo over the dorsum of left hand.

A purpuric eruption may be an unusual early manifestation of mycosis fungoides (MF). On the other hand, persistent pigmented purpuric dermatoses (PPPD) may, occasionally, evolve to cutaneous T-cell lymphoma. Coexistence of these two conditions has been reported, but it is extremely rare. We present the case of an elderly woman with a long-standing pruritic, pigmented purpuric eruption. On 1-year follow-up, histological features suggesting early MF were observed and molecular analysis of the rearrangement of T-cell receptor genes revealed clonality. Our patient may represent a case of PPPD evolving to MF, a case of MF clinically featuring PPPD, or an intermediate condition in a nosological continuity extending from PPPD to MF. A persistent pigmented purpuric eruption may rarely be a harbinger of cutaneous T-cell lymphoma. Therefore, vigilant long-term follow-up of PPPD is highly recommended.