The International Contact Dermatitis Research Group proposes a classification for the clinical presentation of contact allergy. The classification is based primarily on the mode of clinical presentation. The categories are direct exposure/contact dermatitis, mimicking or exacerbation of preexisting eczema, multifactorial dermatitis including allergic contact dermatitis, by proxy, mimicking angioedema, airborne contact dermatitis, photo-induced contact dermatitis, systemic contact dermatitis, noneczematous contact dermatitis, contact urticaria, protein contact dermatitis, respiratory/mucosal symptoms, oral contact dermatitis, erythroderma/exfoliative dermatitis, minor forms of presentation, and extracutaneous manifestations.

Several authors have commented upon the skills of detection required in making a diagnosis of allergic contact dermatitis. Here, we emphasise the search for clues in a systematic manner. We describe four stages as part of a systematic method for diagnosing allergic contact dermatitis. Firstly, elimination (or inclusion) of non-allergic diagnoses. Secondly, perception: the pre-patch test diagnosis and the 'three scenarios' principle. Thirdly, detection: optimising the sensitivity of the patch test process. Fourthly, deduction: diagnosing allergic contact dermatitis by associating the dermatitis with the allergen exposure. We further compare and contrast the pre-patch test history and examination with the markedly different one ('microhistory' and 'microexamination') used after patch testing. The importance of knowledge of contact dermatitis literature is emphasised with a review of recent publications. Finally, we also highlight the use of contact allergy profiling as an investigative tool in the diagnosis of allergic contact dermatitis.

No abstract

Systemic contact dermatitis (SCD) is a condition occurring in previously sensitized individuals after systemic re‐exposure to the same or cross‐reacting substance. Pigmented systemic contact dermatitis after intake of cobalt containing diet has never been reported.

No abstract

No abstract

Background: Drug patch test to identify Cutaneous Adverse Drug reactions (CADRs) has been widely reported. Appropriate vehicles can improve the ability of drug delivery and significantly increase positive reaction of drug patch tests. Objective: To evaluate the efficacy of drug patch tests using 0.9% saline vehicle in comparison with other traditional vehicles in CADRs. Method: All patients were patch tested with suspected drugs using 10-30% concentration of the commercialized form of drugs diluted in 0.9% saline, petrolatum and water. Result: Of 100 patients with CADRs, 54 of those had at least one positive drug patch test. In terms of vehicles used, 43 patients had positive drug patch test with saline as compared to 35 with water (p=0.485) and 25 with petrolatum (p=0.007*). Among CADRs subgroup, saline rendered significantly higher positive rate when compared with petrolatum in drug rash with eosinophilia and systemic symptom (DRESS) (70% vs 20%, p=0.025), maculopapular rash (MP) (52.4% vs 31%, p=0.046) and lichenoid drug eruption (46.7% vs 0.0%, p=0.002). 12/54 (22.2%) of CADRs patients had positive reaction with saline alone. Among these patients, 4/12 (33.3%) were lichenoid drug reaction, 3/12 (25%) were DRESS and 2/12 (16.7%) were MP rash. Allopurinol was the drug giving positive patch test only with saline. Conclusion: Appropriate vehicles is essential to obtain the positive drug patch test. Using saline as a vehicle can increase the positive reaction of drug patch test, particularly in lichenoid drug eruption. We recommend the use of saline as another traditional vehicle in drug patch test.

Gonococcal urethritis (GU) is the second most common sexually transmitted infection (STI). Epidemiologic studies of the situation of GU reinfection and its related risk factors among patients with a history of GU in Thailand remain somewhat limited. A hospital-based retrospective cohort study was conducted between January 1, 2010 and December 31, 2020 to determine the incidence and risk factors of GU reinfection among male patients visiting in Royal Thai Army (RTA) Hospitals. A total of 2,465 male patients presenting a history of GU was included in this study. In all, 147 (6.0%; 95% CI 5.1–6.9) male patients presented GU reinfection, representing an incidence rate of 1.3 (95% CI 1.1–1.5) per 100 person-years. The independent risk factors for GU reinfection were age < 30 years (AHR 1.7; 95% CI 1.0–2.8), number of sexual partners equal to 2 (AHR 3.4; 95% CI 1.0–11.2), $$\ge$$ ≥ 3 (AHR 5.6; 95% CI 2.7–11.6), and participants residing in the north (AHR 4.1; 95% CI 2.3–7.5) and northeast regions (AHR 2.1; 95% CI 1.1–3.9). Incidence of GU reinfection among male patients visiting RTA Hospitals was significantly high among younger aged patients, especially in the north and northeast regions. Multiple sex partners played a major role in GU reinfection. Effective STI prevention programs should be provided to alleviate reinfection and its complications.