Summary Background Direct immunofluorescence (DIF) findings in patients with livedoid vasculopathy (LV) may have benefits for disease differentiation when clinical presentations and/or histopathological findings are inconclusive. Aim To investigate DIF findings in patients with a clinical and histopathological diagnosis of LV. Methods DIF findings of 62 patients with LV were analysed, and the published literature in the PubMed database was also reviewed and summarized. Results This study demonstrated deposition of immunoreactants in blood vessels (BVs) in 59 of the 62 patients (95.2%), and almost all cases were positive for a combination of multiple immunoreactants. Complement C3 and IgM formed the most common combination. The most common pattern was deposition in BVs and at the dermoepidermal junction (DEJ) (59.3%), followed by deposition in BVs alone (40.7%). Immunoreactant deposition in BVs involved superficial BVs with or without deep BVs. The median age of patients with positive DIF findings was significantly higher than that of patients with negative DIF findings for LV (P < 0.03). More recent lesions (present for < 6 months) had a significantly higher percentage of positive results than older lesions (present for ≥ 6 months) (85.2% vs. 14.8%, respectively; P < 0.001). Conclusion In both the present study and in the published literature, DIF study in patients with LV showed positive immunoreactants ranging from 42.9% to 100%. C3 and IgM were the most common immunoreactants deposited in BVs, while the most common pattern was immunoreactant deposition in BVs and at the DEJ. Older patients and those with more recent lesions (< 6 months) had a significantly higher percentage of positive DIF results for LV than did younger patients and those with older lesions (≥ 6 months).

Livedoid vasculopathy (LV) is an uncommon, chronic, and recurrent thrombo‐occlusive vascular disorder. Data specific to LV in Thai population remains scarce. This study aimed to evaluate the clinical course and treatment outcomes of LV in Thai patients, and to perform a literature review for studies that reported on anticoagulant treatment in LV. Seventy‐four patients with a mean age of 37.6 ± 14.7 years were included. The female to male ratio was 5.2:1, and the median follow‐up was 10.5 months. Most patients had primary LV disorder. Forty‐eight patients were improved with treatments, with a median duration of 11.4 months. Combination treatments were commonly used, including anti‐inflammatories, antiplatelets, and immunosuppressants. Add‐on therapy with anticoagulant or psoralen plus ultraviolet‐A (PUVA) led to disease improvement in a majority of the patients treated. Kaplan‐Meier analysis demonstrated that 38.5%, 53.7%, and 57.9% would have disease improvement at 1, 2, and 3 years, respectively. Of 39 studies (n = 219) that reported on anticoagulant treatment in LV, anticoagulant drug was used as monotherapy in 104 patients. The mean duration of anticoagulant treatment was 7.2 ± 3.8 months, which led to disease improvement in 97 patients (93.3%). Bleeding side effect was found in 9 patients (8.7%). The highest incidence of LV was found among females aged 30 to 40 years. Combination therapy with anti‐inflammatory drugs, antiplatelet drugs, and immunosuppressants led to disease improvement. The observed efficacy of add‐on PUVA or anticoagulant is promising and should be further investigated. Further studies are needed to guide the development of an LV management guideline.

Cutaneous manifestations of lupus erythematosus (LE) have a variety of clinical phenotypes and require proper investigation for diagnosis. Knowledge of the direct immunofluorescence (DIF) technique has improved and played an important role in the diagnosis of cutaneous LE. This review explores and summarizes reported DIF findings of each cutaneous LE variant.  Historically, DIF findings of cutaneous LE have revealed deposits of multiple immunoreactants at the dermo-epidermal junction with either linear or granular patterns. Immunoglobulin M is the most common immunoreactant and DIF findings of cutaneous LE variants overlap. Therefore, diagnosis of cutaneous LE requires a combination of monitoring patient history, physical examinations and laboratory studies. This review helps interpret and better understand the application of DIF studies in cutaneous LE.