Photopatch and UV-irradiated patch testing in photosensitive dermatitis

Effects of Hydroxysafflor Yellow A (HSYA) on UVA-Induced Damage in HaCaT Keratinocytes

To assess the effects of hydroxysafflor yellow A (HSYA) on ultraviolet A (UVA)-induced damage in HaCaT keratinocytes. HaCaT keratinocytes were UVA-irradiated, and the effects of HSYA on cell viability, reactive oxygen species (ROS) generation, lipid peroxidation, and messenger (m)RNA expression were measured. mRNA expressions of matrix metalloproteinase (MMP)-1, MMP-2, MMP-9, and cyclooxygenase (COX)-2 were determined by a real-time polymerase chain reaction (RT-PCR). UVA exposure led to a decrease in cell viability and an increase in ROS generation in HaCaT keratinocytes. HSYA effectively increased the viability of HaCaT keratinocytes after UVA exposure and protected them from UVA-induced oxidative stress. Moreover, HSYA inhibited expressions of MMP-1, MMP-2, MMP-9, and COX-2 by HaCaT keratinocytes with UVA-induced photodamage. Our results suggest that HSYA can act as a free radical scavenger when keratinocytes are photodamaged. HSYA has the potential to be a skin-protective ingredient against UVA-induced photodamage.

Ultraviolet diagnostic and treatment modalities in the coronavirus disease 2019 pandemic

Ultraviolet (UV) therapy is an effective and well-tolerated therapeutic method for various dermatologic conditions due to its antiproliferative and immunosuppressive effects. Contemporary phototherapy includes broadband UVB, narrowband UVB, UVA1, PUVA, and excimer laser therapy. The coronavirus disease 2019 pandemic has resulted in the closure of many patient care facilities, including phototherapy units worldwide. Home phototherapy, thalassotherapy, and other UV therapy modalities are an alternative for many patients with chronic dermatoses. We highlighted possible interactions of UV therapy effects and the coronavirus disease 2019 pandemic, and focused on organization and measures against transmission of infections in phototherapy units. Dermatology departments have reopened their units, assessing the risks and benefits for patients, optimizing safety regulations, and adhering to the rules for disinfection.

Photopatch Testing in New Zealand: A 12-Year Retrospective Review

BACKGROUND

Little is known about the common photoallergens in New Zealand, where ultraviolet exposure is particularly high. Availability of photopatch testing is limited because of it being performed in very few tertiary referral and contact dermatitis clinics.

OBJECTIVE

To review the photopatch testing experience in New Zealand.

METHOD

A retrospective review of all patients who underwent photopatch testing at a tertiary referral center in Auckland from 2008 to 2019 was performed.

RESULTS

Seventy patients had photopatch testing over the 12-year period. Of the 58 patients tested using the photoallergen series, 6 (10%) patients had a positive photopatch test reaction, of which 4 were to promethazine and 2 were to benzophenone-3. The most common postpatch diagnosis was endogenous dermatitis (54%), followed by allergic contact dermatitis (21%), photoallergic contact dermatitis (9%), and chronic actinic dermatitis (4%).

CONCLUSIONS

Both patch and photopatch testing are important investigations in patients with suspected photoallergic contact dermatitis. Promethazine and benzophenone-3 were the most frequent and only photoallergens in our population. Promethazine sensitization was via oral exposure, supporting a mechanism of systematized photoallergy to promethazine.

Photopatch testing in a tropical country, Thailand: 20 years' experience

BACKGROUND

Photoallergic contact dermatitis is one of the important parts of photodermatoses. The investigation of choice is photopatch testing. However, reports with photopatch test results from Asian countries are scarce. The objective of this study was to determine the prevalence of positive photopatch test reactions and to ascertain the common photoallergens among Thai patients during 1998-2018.

METHODS

We retrospectively reviewed the records of 339 patients who were clinically suspected of having photoallergic contact dermatitis and had undergone photopatch testing.

RESULTS

A total of 44 photoallergic contact reactions in 38 patients (11.2%) were found. The positive photoallergic reactions were mainly found with organic ultraviolet filters and fragrances.

CONCLUSIONS

Organic ultraviolet filter chemicals especially benzophenone-3 and fragrances were found to have a high prevalence of photoallergic contact reactions. Monitoring of the photoallergens employed in photopatch tests should be conducted periodically to provide the best patient care.