An unusual presentation of a common condition: Allergic contact dermatitis.

Allergic contact dermatitis commonly affects patients with chronic venous leg ulcers and can contribute to impaired wound healing. Many allergens have been identified, and despite the use of advanced dressings, the incidence of allergy has remained high. We discuss an unusual presentation of allergic contact dermatitis in a patient with a chronic wound. The patient's history was consistent with a recurrent venous leg ulcer, but on this occasion, the wound continued to deteriorate despite optimal treatment. This prompted further investigation, which included patch testing. Although the clinical features were not suggestive of allergy, the patch test was positive for several allergens, including Atrauman® dressings, which the patient was using at the time. This case highlights the importance of regular reassessment and accurate diagnosis for the management of chronic wounds. It also demonstrates that allergic contact dermatitis can contribute to delayed wound healing without causing the classical clinical features of inflammation of the surrounding skin, and even hypoallergenic, non-adherent dressings can be sensitising.

Para-phenylenediamine allergy: current perspectives on diagnosis and management.

Para-phenylenediamine (PPD) is the commonest and most well-known component of hair dyes. Oxidative hair dyes and dark henna temporary tattoos contain PPD. Individuals may be sensitized to PPD by temporary henna tattooing in addition to dyeing their hair. PPD allergy can cause severe reactions and may result in complications. In recent years, frequency of positive patch test reactions to PPD has been increasing. Cross-sensitization to other contact allergens may occur, in particular to other hair dye components. Hairdressers are at a high risk for PPD allergy and require counseling regarding techniques to minimize exposure and protective measures while handling hair dye. We focus this review on the current perspectives of diagnosis and management of PPD allergy.

Benzophenone 4: an emerging allergen in cosmetics and toiletries?

Chemical ultraviolet (UV) filters have, over the last few decades, been increasingly used not only in conventional sunscreen products but also in many cosmetics and toiletries. Allergic contact dermatitis as well as photoallergic contact dermatitis reactions have been well documented as a consequence of such use. Over a 3-year period, we recorded the number of positive patch test reactions to a selection of chemical UV filters that we added to our usual cosmetics/facial series. Our objective was to investigate whether any of these filters produced significant numbers of positive patch test results in the absence of photostimulation. Our results show that not only did benzophenone 4 (2-hydroxy-4-methoxybenzophenone-5-sulphonic acid: sulisobenzone) produce significantly more positive patch test results than the other UV filters that were tested, but also it was the third most frequently positive result overall. Our findings would support the inclusion of benzophenone 4 when patch testing to investigate likely contact dermatitis from cosmetics and toiletries.

Toilet seat contact dermatitis.

Allergic contact dermatitis to wooden toilet seats was a previously well-recognized pattern of regional dermatitis. We report a recent occurrence in a child that highlights a possible resurgence in this presentation, associated with the increasing popularity of wooden toilet seats.

A multicentre review of the hairdressing allergens tested in the UK.

Allergens used for patch testing in the hairdressing series vary between dermatology centres in the UK. The aim of our study is to ascertain the hairdressing allergens currently in use and their test results in several dermatology centres in the UK. Data were obtained from databases in 9 dermatology departments. The allergens with positive results and current/past relevance were included in a new hairdressing series based on collective experience, for wider use and further evaluation.

A multicentre review of the footwear allergens tested in the UK.

Footwear allergens used for patch testing vary between dermatology centres in the UK. The aim of our study is to ascertain the footwear allergens currently in use and their test results in several dermatology centres in the UK. Data were obtained from databases in 9 dermatology departments. A new footwear series consisting of 19 allergens including those with positive results and current/past relevance in this study based on collective experience is proposed for wider use and further evaluation.