Authors Reply: Chronic venous disease, platelet and haemostatic abnormalities contribute to the pathogenesis of pigmented purpuric dermatoses.

Dear Editor, We thank you for drawing our attention the letter of Yetkin et al. entitled Pigmented Purpuric Dermatosis-Ecchymosis and Chronic Venous Disease in response to our paper Chronic venous disease, platelet and haemostatic abnormalities contribute to the pathogenesis of pigmented purpuric dermatoses. The authors of the letter have erroneously interpreted ecchymosis and purpura to be synonymous with pigmented purpuric dermatosis (PPD, also known as capillaritis). While ecchymosis is the clinical manifestation of an anatomical bleed, PPD is a distinct dermatological condition with a complex aetiology that is vastly distinct from a simple purpura or ecchymosis. The diagnosis of PPD is confirmed by a biopsy of the affected lesion where histology would typically reveal a perivascular lymphocytic infiltrate and a dermal red cell extravasation. In some sub-categories of PPD, a lichenoid infiltrate, dermal spongiosis or a granulomatous component may be present. PPD is a differential diagnosis for variants of cutaneous T-cell lymphoma (CTCL) and in particular the angiocentric mycosis fungoides (CTCL) that may clinically resemble PPD. It has also been suggested that PPD may be a precursor of CTCL. Various other conditions and in particular cutaneous sarcoidosis may resemble PPD. Hence, a PPD eruption should not be dismissed as simple purpura or pigmentation and appropriate dermatological assessment including a biopsy should be carried out. The novel finding of our study is that patients with PPD would benefit from further assessment of congenital or acquired haemostatic abnormalities that result in thrombocytopenia or affect platelet function. In particular we demonstrated that drugs or supplements such as fish oil may inhibit platelet function contributing to the pathogenesis of PPD. We recommended cessation of any modifiable risk factor when clinically appropriate and treatment of an underlying chronic venous disease when present. Many dermatological conditions may appear clinically similar to non-dermatologists and the confusion is exacerbated when different conditions are titled containing a similar lexicon. Not all conditions containing the term purpura indicate simple bruising as evident from the range of conditions containing the term purpura including PPD, Henoch-Schonlein purpura (IgA vasculitis), thrombotic thrombocytopenic purpura (TTP) and immune-mediated thrombocytopenia (immune thrombocytopenic purpura; ITP). A referral to a dermatologist and appropriate histological confirmation of the clinical diagnosis is recommended when practitioners are dealing with unusual pigmented or purpuric conditions.