Human Leukocyte Antigen Markers for Distinguishing Pustular Psoriasis and Adult-Onset Immunodeficiency with Pustular Reaction.

Pustular skin diseases, with pustular psoriasis (PP) being the prototype, are immune-mediated diseases characterized by the presence of multiple pustules, resulting from neutrophil accumulation in the layer of epidermis. Sterile skin pustular eruption, like PP, is also observed in 20-30% of patients with adult-onset immunodeficiency syndrome (AOID) and anti-interferon γ autoantibodies (IFN-γ), leading to challenges in classification and diagnosis. While the mechanism underlying this similar phenotype remains unknown, genetic factors in relation to the immune system are suspected of playing an important role. Here, the association between human leukocyte antigen (HLA) genes, which play essential roles in antigen presentation, contributing to immune response, and the presence of skin pustules in AOID and PP was revealed. HLA genotyping of 41 patients from multiple centers in Thailand who presented with multiple sterile skin pustules (17 AOID patients and 24 PP patients) was conducted using a next-generation-sequencing-based approach. In comparison to healthy controls, HLA-B*13:01 (OR = 3.825, 95%CI: 2.08-7.035), C*03:04 (OR = 3.665, 95%CI: 2.102-6.39), and DQB1*05:02 (OR = 2.134, 95%CI: 1.326-3.434) were significantly associated with the group of aforementioned conditions having sterile cutaneous pustules, suggesting a common genetic-related mechanism. We found that DPB1*05:01 (OR = 3.851, p = 0.008) and DRB1*15:02 (OR = 3.195, p = 0.033) have a significant association with pustular reaction in AOID patients, with PP patients used as a control. A variant in the DRB1 gene, rs17885482 (OR = 9.073, p = 0.005), was observed to be a risk factor for PP when using AOID patients who had pustular reactions as a control group. DPB1*05:01 and DRB1*15:02 alleles, as well as the rs17885482 variant in the DRB1 gene, were proposed as novel biomarkers to differentiate PP and AOID patients who first present with multiple sterile skin pustules without known documented underlying conditions.

Comparative immunohistochemical analysis of inflammatory cytokines in distinct subtypes of Sweet syndrome.

Background: A dysregulated immune response has been implicated in Sweet syndrome (SS) pathogenesis; however, cytokine profiles across different conditions associated with SS - including adult-onset immunodeficiency (AOID) due to anti-interferon (IFN)-γ autoantibodies - remain unknown. Objective: To investigate alterations in inflammatory cytokines in skin lesions of distinct subtypes of SS. Methods: Skin biopsies were collected from 42 AOID- and 52 non-AOID-associated SS patients and 18 healthy controls. The comparative immunohistochemical study was conducted using monoclonal antibodies against interleukin (IL)-1ß, IL-6, IL-17, IFN-γ, and tumor necrosis factor-α on paraffin-embedded sections. The quantitative percentage positivity and intensity were calculated using computer-based image analysis. Results: The results showed stronger and more diffuse dermal immunoreactivity for IFN-γ and IL-17 in the AOID-associated (p < 0.001 and p < 0.001, respectively) and non-AOID-associated SS (p < 0.001 and p < 0.001, respectively) groups. However, no significant differences in the levels of these two cytokines were observed between the AOID- and non-AOID-associated SS groups. Increased expression of IFN-γ together with IL-17 was also noted in almost all subtypes among non-AOID-associated SS. Conclusions: These results demonstrate that IFN-γ and IL-17 are implicated in immunopathology of all SS subtypes, including AOID-associated SS, despite the presence of anti-IFN-γ autoantibodies.

Pythiosis presenting with chronic swelling and painful subcutaneous lesion at right deltoid.

Pythiosis is a fatal disease which has high incidence in tropical regions. In contrast with vascular pythiosis, cutaneous and subcutaneous pythiosis are both uncommon. Here, we report a case of subcutaneous pythiosis in a pregnant farmer manifested with a progressively larger and more painful mass at right deltoid. The tissue culture and molecular test were negative for fungi. The diagnosis was supported by the positivity of serum immunochromatographic test (ICT) for pythiosis. Patients responded well to the combination therapy of itraconazole, terbinafine and azithromycin.

Reactive Neutrophilic Dermatoses in Adult-Onset Immunodeficiency due to Interferon-Gamma Autoantibody and Their Associated Factors.

BACKGROUND: Adult-onset immunodeficiency (AOID) due to interferon-gamma autoantibody is a rare, acquired immunodeficiency disease. Reactive neutrophilic dermatoses (RND), predominantly Sweet syndrome (SS), and generalized pustular eruption have been reported repeatedly. OBJECTIVES: The aims of this study were to describe the cutaneous manifestations in AOID patients and determine the incidence of RND and associated factors using a larger population size than have been previously reported. METHODS: A retrospective chart review of all confirmed AOID cases in Chiang Mai University Hospital from January 2006 to June 2020 was conducted. The demographics and characteristics of RND including type, onset, and laboratory information in every episode of cutaneous manifestations were collected. Generalized estimating equations of binary logistic regression were used to determine the indicators of RND. RESULTS: A total of 146 patients with confirmed AOID were identified. Of these, 57 cases (39%) developed at least one episode of RND. Thirteen cases (23%) of the patients experienced RND twice during the follow-up period. All recurrence of RND displayed the same cutaneous phenotype, with the exception of 2 cases who had both SS and generalized pustular eruption. Finally, 49 episodes of SS and 22 episodes of generalized pustular eruption were included in the analysis. All patients with RND had concomitant active opportunistic infections, of which most were non-tuberculous mycobacterium (NTM) infection. NTM infection (prevalence odds ratio [POR] 2.87), lymphadenopathy (POR 3.30) as well as lower serum alkaline phosphatase (ALP) level (POR 0.71 for every 100-unit increment in ALP) were found to be significantly associated with RND occurrence. CONCLUSIONS: 39% of our AOID patients experienced RND once during the course of the disease. Notable factors associated with RND occurrence were concomitant NTM infection, lymphadenopathy, and lower level of ALP.

Incidence and factors associated with cutaneous immune-related adverse events to immune check point inhibitors: An ambispective cohort study.

Background: Although immune checkpoint inhibitors (ICIs) have become the frontline treatment option for patients with various advanced cancers due to improved survival, they can be associated with a spectrum of cutaneous immune-related adverse events (cirAEs). However, little is known regarding the occurrence and patterns of cirAE-related ICI therapy in patients of different races other than white populations. Therefore, we investigated the incidence and associated factors of cirAEs among cancer patients in northern Thailand. Methods: A referral-center-based ambispective cohort study was conducted from January 1, 2017, to March 31, 2021. Based on a linked database and merged patient-level data, adult patients with pathologically confirmed cancer who were diagnosed and received ICI therapy regardless of cancer type and followed up through August 31, 2021, were included. All cirAE-related ICI therapy was based on clinical evaluation and ascertainment by a board-certified dermatologist. The incidence of cirAE-related ICI therapy with confidence intervals (CIs) across cancer- and ICI therapy-specific groups was estimated. Factors associated with cirAEs were evaluated using multivariable modified Poisson regression to estimate risk ratios (RRs) and 95% CIs. Results: The study included 112 patients (67 men [59.8%]; mean age, 65.0 [range, 31.0-88.0] years), who were mainly diagnosed with lung cancer (56.3%), followed by liver cancer (19.6%). The overall incidence of cirAE-related ICI therapy was 32.1% (95% CI, 24.1-41.4); however, there was no substantial difference in sex, cancer type, or individual ICI therapy. The two identified prognostic risk factors of cirAE-related ICI therapy were age >75 years (adjusted RR, 2.13; 95% CI, 1.09-4.15; P=0.027) and pre-existing chronic kidney disease stages 3-4 (adjusted RR, 3.52; 95% CI, 2.33-5.31; P<0.001). Conclusions: The incidence of cirAE-related ICI therapy among Thai cancer patients was comparable to that in white populations. Early identification, particularly in elderly patients and those with CKD, should be implemented in clinical practice to help optimize therapeutic decision-making and patient health outcomes.

Use of Thiazide Diuretics and Risk of All Types of Skin Cancers: An Updated Systematic Review and Meta-Analysis.

Background: The use of thiazide diuretics is associated with skin cancer risk; however, whether this applies to all skin cancer types is unclear. Methods: In this meta-analysis, we searched multiple electronic databases and gray literature up to 10 April 2022, with no language restrictions, to identify relevant randomized controlled trials (RCTs) and non-randomized studies (cohort, case-control) that investigated the association between thiazide diuretics and skin cancer. The primary outcomes of interest were malignant melanoma and non-melanoma skin cancer (basal cell carcinoma [BCC], squamous cell carcinoma [SCC]). Secondary outcomes included other skin cancers (lip cancer, Merkel cell carcinoma, malignant adnexal skin tumors, oral cavity cancer, and precursors of skin cancer). We used a random-effects meta-analysis to estimate pooled adjusted odds ratios (ORs) and 95% confidence intervals (CIs). Results: Thirty non-randomized studies (17 case-control, 13 cohort, no RCTs) were included. Thiazide diuretic users had a higher risk of malignant melanoma (17 studies; n = 10,129,196; pooled adjusted OR, 1.10; 95% CI, 1.04−1.15; p < 0.001; strength of evidence, very low; very small harmful effect), BCC (14 studies; n = 19,780,476; pooled adjusted OR, 1.05; 95% CI, 1.02−1.09; p = 0.003; strength of evidence, very low; very small harmful effect), and SCC (16 studies; n = 16,387,862; pooled adjusted OR, 1.35; 95% CI, 1.22−1.48; p < 0.001; strength of evidence, very low; very small harmful effect) than non-users. Thiazide diuretic use was also associated with a higher risk of lip cancer (5 studies; n = 161,491; pooled adjusted OR, 1.92; 95% CI, 1.52−2.42; p < 0.001; strength of evidence, very low; small harmful effect), whereas other secondary outcomes were inconclusive. Conclusions: Thiazide diuretics are associated with the risk of all skin cancer types, including malignant melanoma; thus, they should be used with caution in clinical practice.

Acitretin treatment in antimalarial-refractory/intolerant discoid lupus erythematosus: A prospective, open-label, uncontrolled study.

BACKGROUND: The treatment of discoid lupus erythematosus (DLE) is often challenging, especially in patients who are refractory or intolerant to topical treatments and first-line systemic drugs, specifically antimalarial drugs. Although acitretin has been shown to be effective in patients with DLE in a few studies, there is no published study describing the long-term efficacy of acitretin with a validated score. OBJECTIVES: To evaluate the efficacy and safety of acitretin in patients with antimalarial-refractory/intolerant DLE. METHODS: A prospective, open-label, uncontrolled study was conducted in patients with antimalarial-refractory/intolerant DLE. All patients were treated with an initial dosage of 10 mg acitretin daily. Clinical response was assessed using the Revised Cutaneous Lupus Erythematosus Disease Area and Severity Index (RCLASI) at weeks 4, 8, 12, and 24. Acitretin was increased to 25 mg daily unless an adequate response was achieved at week 8. RESULTS: Fourteen patients were recruited. Of these, 10 were antimalarial-refractory and four were antimalarial-intolerant. The acitretin therapy was discontinued in one patient after 20 weeks of treatment because of active systemic disease. Of the 13 remaining patients, the mean RCLASI activity scores declined from 21 ± 9 at baseline to 9 ± 4 at week 24. A significant reduction in RCLASI was initially observed at week four and consistently noted at each follow-up visit (p ≤ 0.01). At the end of the study, a marked response was achieved in approximately 80% of patients. There were no statistically significant differences in the clinical response or in the requirement of the up-dosing of acitretin between the refractory and intolerance groups (p = 0.88 and p = 0.326, respectively). Age ≥50 years old, female sex, and generalized DLE were the favorable prognostic factors. No serious adverse events were noted. CONCLUSIONS: Acitretin appears to be an effective treatment with acceptable safety profiles for antimalarial-refractory/intolerant DLE.

Impact of Pharmacological Treatments for Chronic Spontaneous Urticaria with an Inadequate Response to H1-Antihistamines on Health-Related Quality of Life: A Systematic Review and Network Meta-Analysis.

BACKGROUND: Recently, pharmacological treatment options for H1-antihistamine-refractory chronic spontaneous urticaria have increased dramatically; however, their effects on patient-reported outcomes, including health-related quality of life (HRQOL), remain unclear. OBJECTIVE: To compare the impact of these treatments on HRQOL among H1-antihistamine-refractory patients with chronic spontaneous urticaria. METHODS: We completed a comprehensive search of the available literature in the electronic databases, gray literature, and preprint reports up to April 19, 2021, with no language restrictions. The primary outcome for evaluation was a change in HRQOL from the baseline, and secondary outcomes included patient unacceptability and other patient-reported outcomes. We used a random-effects network meta-analysis and estimated differences in standardized mean differences (SMDs) and odds ratios with 95% CIs. Evidence-based synthesis was based on magnitudes of effect size, evidence certainty, ranking of treatment effects, and clinically meaningful improvement. RESULTS: Twelve randomized controlled trials encompassing 1866 adolescent and adult patients were included. Our evidence synthesis analyses revealed that hydroxychloroquine (SMD, -1.00 [-1.61 to -0.39]), 72 mg ligelizumab (SMD, -0.66 [-0.96 to -0.35]), 240 mg ligelizumab (SMD, -0.67 [-0.98 to -0.37]), and 300 mg omalizumab (SMD, -0.53 [-0.67 to -0.39]) significantly improved HRQOL with a moderate beneficial effect. However, the use of hydroxychloroquine seems to be limited by a higher risk of patient unacceptability of treatment. Other secondary outcomes remain inconclusive based on the available evidence. CONCLUSIONS: Both ligelizumab (72 or 240 mg) and 300 mg omalizumab appeared to be effective treatments for H1-antihistamine-refractory chronic spontaneous urticaria, because they were closely associated with improved HRQOL.

Adult-onset immunodeficiency due to anti-interferon-gamma autoantibody-associated Sweet syndrome: A distinctive entity.

Sweet syndrome (SS) has been increasingly reported in patients with adult-onset immunodeficiency (AOID) due to anti-interferon-γ autoantibody who also have concomitant opportunistic infections, especially disseminated non-tuberculous mycobacterial infection (dNTMI). A retrospective study retrieving data from 2011 through 2020 was conducted. We compared clinical characteristics of SS with and without AOID and generated the prediction model and examined the interaction between AOID and dNTMI in the occurrence of SS. Lymphadenopathy, pustular lesions, and leukocytosis are the significant predictors for AOID-associated SS. Adjusted risk differences were 0.58 (95% confidence interval [CI], 0.33-0.83), 0.21 (95% CI, 0.02-0.39), and 0.24 (95% CI, 0.01-0.47), respectively. Based on the analysis of aggregated cross-sectional data, both the overall and the direct effect of AOID increased the prevalence of SS. The indirect effect of AOID on the occurrence of SS might also be mediated through dNTMI or other common opportunistic infections. In addition, there was a trend of positive additive interaction between AOID and dNTMI. Although the test of additive interaction did not reveal statistically significant results, a deviation from additivity of isolated effects might suggest potential causal interaction between AOID and dNTMI. The distinctive clinical syndrome comprising lymphadenopathy, pustular lesions, and leukocytosis in patients with SS should raise the awareness of clinicians to the potential of underlying AOID.

A case of dengue fever presenting with acute urticaria.

BACKGROUND: Acute urticaria (AU) is characterized by the occurrence of spontaneous wheals, angioedema, or both for less than 6 weeks. Viral infection is considered to be one of the common causes of AU, however AU has never been reported in association with dengue infection. OBJECTIVE: To describe the first case of AU in dengue virus infection. METHODS: Case report. RESULTS: A 17-year-old healthy male presented with first episode of AU which associated with confirmed dengue virus infection. He responded well with antihistamine treatment and without recurrence at 2-month follow up. CONCLUSIONS: Patients with dengue virus infections can present with AU, possibly from viral-infected mast cell. Future research will have to clarify this association.

Epidemiology and clinical features of pustular psoriasis: A 15-year retrospective cohort.

Pustular psoriasis (PuP) is a rare variant of psoriasis with a unique immunopathogenesis, unlike its more prevalent plaque-type counterpart. However, data available are limited due to its low prevalence. This study aimed to describe the demographic profile, precipitating factors, clinical presentations, and treatments among patients with different PuP subtypes from a 15-year retrospective cohort study in Thailand. A total of 60 patients were included in this study. There was female predominance (73.3%) and mean age of onset was 38.1 ± 17.6 years. Generalized PuP (GPP) was the most prevalent subtype (80.0%), followed by acrodermatitis continua of Hallopeau (13.3%) and palmoplantar pustulosis (6.7%). Precipitating factors included corticosteroid withdrawal, upper respiratory tract infection, and pregnancy. One-third of PuP occurred concomitantly with other psoriasis variants, especially the plaque type. The most prescribed systemic and topical treatments were oral acitretin (60.0%) and topical corticosteroids (98.3%), respectively. Only two patients were treated with narrow-band ultraviolet B. In conclusion, four out of every five PuP patients in this center had GPP. Corticosteroid withdrawal, upper respiratory tract infection, and pregnancy are important precipitating factors. Coexistence with other psoriasis variants was identified in one out of every three patients. Acitretin remains the mainstay of systemic treatment.

Evaluation of Pharmacologic Treatments for H1 Antihistamine-Refractory Chronic Spontaneous Urticaria: A Systematic Review and Network Meta-analysis.

IMPORTANCE: The comparative benefits and harms of all available treatments for H1 antihistamine-refractory chronic spontaneous urticaria (CSU) have not been established. OBJECTIVE: To evaluate different treatment effects of pharmacologic treatments among patients with H1 antihistamine-refractory CSU. DATA SOURCES: Searches were conducted of MEDLINE, Embase, PubMed, Cochrane Library, Web of Science, Scopus, and CINAHL from inception to April 19, 2021, with no language restrictions. Gray literature from Google Scholar, ongoing trial registers, and preprint reports was added to the searches of electronic databases. STUDY SELECTION: Randomized clinical trials using validated measurement tools that investigated the benefits and harms of pharmacologic treatments among adolescent or adult patients with CSU who had an inadequate response to H1 antihistamines were screened for inclusion independently by 2 investigators. DATA EXTRACTION AND SYNTHESIS: Two investigators independently extracted study data according to the predefined list of interests. A random-effects model was used to calculate the network estimates reported as standardized mean differences and odds ratios with corresponding 95% CIs. MAIN OUTCOMES AND MEASURES: The primary outcomes that reflect the patient's perspective included changes in urticaria symptoms from baseline and unacceptability of treatment (all-cause dropouts). RESULTS: Twenty-three randomized clinical trials with 2480 participants that compared 18 different interventions or dosages and placebo were included. The standardized mean differences for change in urticaria symptoms were -1.05 (95% CI, -1.37 to -0.73) for ligelizumab, 72 mg; -1.07 (95% CI, -1.39 to -0.75) for ligelizumab, 240 mg; -0.77 (95% CI, -0.91 to -0.63) for omalizumab, 300 mg; and -0.59 (95% CI, -1.10 to -0.08) for omalizumab, 600 mg. No significant differences in treatment unacceptability were observed. With respect to benefits and harms, the network estimates illustrated that the most efficacious treatments were achieved with ligelizumab, 72 or 240 mg (large beneficial effect) and omalizumab, 300 or 600 mg (moderate beneficial effect). CONCLUSIONS AND RELEVANCE: The findings in this meta-analysis suggest that the biologic agents ligelizumab, 72 or 240 mg, and omalizumab, 300 or 600 mg, can be recommended as effective treatments for patients with CSU who have had an inadequate response to H1 antihistamines. Head-to-head trials with high methodologic quality and harmonized design and outcome definitions are needed to help inform subsequent international guidelines for the management of CSU.

Sweet syndrome as a cutaneous manifestation in a patient with Erysipelothrix rhusiopathiae bacteremia: A case report.

Erysipelothrix rhusiopathiae is a gram-positive bacillus causing three clinical syndromes in humans, including localized cutaneous infection, diffuse cutaneous form, and systemic infection. Various skin lesions in systemic form have been reported; however, no comprehensive study has been conducted. Here we report a case of a 60-year-old woman who suffered from E. rhusiopathiae bacteremia with distinct generalized annular purplish plaques. Negative microbiological studies of the lesional skin sample combined with the histopathological study showing diffuse neutrophilic infiltration confirm the diagnosis of Sweet syndrome. This study documents Sweet syndrome as one of the cutaneous manifestations in systemic E. rhusiopathiae infection.

Comparative Efficacy and Acceptability of Licensed Dose Second-Generation Antihistamines in Chronic Spontaneous Urticaria: A Network Meta-Analysis.

BACKGROUND: Licensed dose second-generation H1-antihistamines (sgAHs) are the first-line treatment in chronic spontaneous urticaria (CSU). However, the available evidence up to the present is insufficient to rank sgAHs in terms of their efficacy. OBJECTIVES: To study the comparative efficacy and acceptability of all licensed dose sgAHs in CSU treatment. METHODS: We searched PubMed, Scopus, the Cochrane Central Register of Controlled Trials, and Web of Science for randomized controlled trials (RCTs) that included licensed dose sgAHs in CSU treatment up until March 2020. A network meta-analysis was performed to estimate the standardized mean difference (SMD) and 95% confidence interval (CI) from both direct and indirect evidence for efficacy outcomes. The primary outcome was the total symptom score (TSS) changes from baseline. Secondary outcomes were changes in pruritus score and wheal score from baseline. The acceptability was estimated using odds ratios. RESULTS: We identified and included 22 RCTs with 3943 patients for evidence synthesis. Olopatadine, fexofenadine, bilastine, rupatadine, and levocetirizine were more efficacious than placebo in TSS. Olopatadine was ranked first for all efficacy outcomes (TSS: SMD -1.26 [95% CI: -1.94 to -0.58], pruritus score: SMD -0.82 [95% CI: -1.30 to -0.35], and wheal score: SMD -0.65 [95% CI: -1.10 to -0.55]). The acceptability of all included sgAHs was not inferior to the placebo. CONCLUSIONS: Olopatadine, fexofenadine, bilastine, rupatadine, and levocetirizine demonstrate superior therapeutic efficacy to placebo for the treatment of patients with CSU. Because of the low to very low quality of almost all studies included in this study, rigorous head-to-head trials are needed to confirm our findings.

Degos-like lesions as a cutaneous manifestation of cytomegalovirus infection: A rare and serious complication in a patient with drug-induced hypersensitivity syndrome.

Cytomegalovirus causes a myriad of clinical features, potentially affecting any organ system, significantly increasing morbidity and even mortality. Vascular endothelial cell infection by cytomegalovirus has been implicated in the development of vasculopathy, possibly accounting for the clinical association between cytomegalovirus and vascular thrombosis. In contrast with visceral organ involvement, the cutaneous manifestations of cytomegalovirus are variable and rarely described. Malignant atrophic papulosis, commonly known as Degos disease, is an unusual small vessel arteriopathy with a pathognomonic clinical appearance of atrophic porcelain-white central papules surrounded by telangiectatic erythema. As with the arterial occlusive process, Degos disease may be idiopathic or secondary to autoimmune disorders or viral infection. All in all, cytomegalovirus-related Degos-like presentation has never been described. This report describes a case in which disseminated cytomegalovirus disease developed 4 weeks after the onset of drug-induced hypersensitivity syndrome with prominent Degos-like skin lesions. Our case highlights a rare example of Degos-like lesions occurring due to cytomegalovirus disease and emphasizes the importance of early recognition of the characteristic cutaneous eruption as a diagnostic clue leading to the prompt management of this life-threatening infection.

Phaeohyphomycosis caused by Diaporthe phaseolorum in an immunocompetent patient in Thailand: a case report.

Phaeohyphomycosis is caused by a large, heterogeneous group of darkly pigmented fungi. It is an infrequent infection in humans. However, the prevalence has been increasing in recent years especially in immunocompromised patients. Diaporthe phaseolorum is a common black fungal pathogen of plants, which rarely causes human infection. We report the first case of cutaneous infection caused by Diaporthe phaseolorum in an immunocompetent host and the first in Asia. Although, the review of the literature revealed two previous cases of cutaneous infection caused by this organism, both of them were in immunocompromised hosts. A slow-growing asymptomatic nodule was the major clinical feature. Histopathological examination showed granulomatous inflammation and pigmented septate hyphae and yeast-like cells. The fungal isolation was identified by morphological characteristics and DNA sequencing. The lesion was resolved after complete surgical excision and oral fluconazole for two months. This report highlights the potential role of Diaporthe phaseolorum as an emerging cause of infection in immunocompetent patients.

Efficacy of acitretin in the treatment of reactive neutrophilic dermatoses in adult-onset immunodeficiency due to interferon-gamma autoantibody.

Reactive neutrophilic dermatoses in adult-onset immunodeficiency due to interferon-γ autoantibody (AOID) are usually associated with concomitant active opportunistic infections. Data focusing on the treatment of these dermatoses with non-immunosuppressive drugs are still lacking. The aim of this study was to assess the efficacy and safety of acitretin treatment of reactive neutrophilic dermatoses in AOID. We conducted a retrospective review of all patients with AOID who had reactive neutrophilic dermatoses and had been treated with acitretin from January 2008 to December 2018. In total, 23 patients had been diagnosed with AOID, with 27 episodes of reactive neutrophilic dermatoses (20 episodes of Sweet syndrome and seven episodes of generalized pustular eruption) and treated with acitretin. The median effective dose of acitretin was 10 mg/day. The mean initial response was 5.6 ± 2.3 days. The rash had almost or completely cleared within 2 weeks in 70.4% of patients. One case had developed a reversible acitretin-induced liver injury with hepatocellular pattern. The median total duration of treatment was 3 months. In conclusion, this study demonstrates the potential role of acitretin as one of the treatments of choice for reactive neutrophilic dermatoses in AOID, attributable to its favorable response and good tolerability.