Photodermatoses in pigmented skin

Clinical characteristics of patients with human immunodeficiency virus and immune-mediated photodermatoses: A retrospective study of 39 patients

BACKGROUND

HIV/AIDS patients are susceptible to various infectious and inflammatory dermatoses. No systemic work has been done on HIV/AIDS patients with immune-mediated photodermatoses in China. Here, we aim to determine the clinical features of immune-mediated photodermatoses in HIV/AIDS patients.

METHODS

A retrospective analysis of HIV/AIDS patients with immune-mediated photodermatoses was carried out with demographic data, clinical characteristics, laboratory data, and follow-up data at the First Affiliated Hospital of Kunming Medical University between 2012 and 2019. The data were subjected to statistical analysis.

RESULTS

A total of 39 HIV/AIDS patients with immune-mediated photodermatoses were enrolled, including 22 cases of polymorphic light eruption (PLE), 16 cases of chronic actinic dermatitis (CAD), and one actinic reticuloid. The CD4 count at the visit of the HIV-positive CAD group was lower than the PLE group (p = .049). The HIV-positive CAD group was more sensitive toward UVB than the PLE group (p = .020) and had a lower MED-UVB value (p = .044). There was no significant difference in UV tests among different categories of skin types.

CONCLUSION

Immune-mediated photodermatoses are a manifestation of the advanced symptom of HIV infection, and sometimes also the presenting feature of HIV infection. Compared with HIV-positive PLE patients, CAD patients showed higher sensitivity to UVB radiation and had a lower MED-UVB value. The primary treatment for immune-mediated photodermatoses in HIV/AIDS patients is HAART and sun avoidance.

Measurement of Melanin Metabolism in Live Cells by [U-13C]-L-Tyrosine Fate Tracing Using Liquid Chromatography-Mass Spectrometry

Melanin synthesis occurs within a specialized organelle called the melanosome. Traditional methods for measuring melanin levels rely on the detection of chemical degradation products of melanin by high-performance liquid chromatography. Although these methods are robust, they are unable to distinguish between melanin synthesis and degradation and are best suited to measure melanin changes over long periods of time. We developed a method that actively measures both eumelanin and pheomelanin synthesis by fate tracing [U-13C] L-tyrosine using liquid chromatography-mass spectrometry. Using this method, we confirmed the previous reports of the differences in melanin synthesis between melanocytes derived from individuals with different skin colors and MC1R genotype and uncovered new information regarding the differential de novo synthesis of eumelanin and pheomelanin, also called mixed melanogenesis. We also revealed that distinct mechanisms that alter melanosomal pH differentially induce new eumelanin and pheomelanin synthesis. Finally, we revealed that the synthesis of L-3,4-dihydroxyphenylalanine, an important metabolite of L-tyrosine, is differentially controlled by multiple factors. Because L-tyrosine fate tracing is compatible with untargeted liquid chromatography-mass spectrometry‒based metabolomics, this approach enables the broad measurement of cellular metabolism in combination with melanin metabolism, and we anticipate that this approach will shed new light on multiple mechanisms of melanogenesis.

Human health in relation to exposure to solar ultraviolet radiation under changing stratospheric ozone and climate

The Montreal Protocol has limited increases in the UV-B (280-315 nm) radiation reaching the Earth's surface as a result of depletion of stratospheric ozone. Nevertheless, the incidence of skin cancers continues to increase in most light-skinned populations, probably due mainly to risky sun exposure behaviour. In locations with strong sun protection programs of long duration, incidence is now reducing in younger age groups. Changes in the epidemiology of UV-induced eye diseases are less clear, due to a lack of data. Exposure to UV radiation plays a role in the development of cataracts, pterygium and possibly age-related macular degeneration; these are major causes of visual impairment world-wide. Photodermatoses and phototoxic reactions to drugs are not uncommon; management of the latter includes recognition of the risks by the prescribing physician. Exposure to UV radiation has benefits for health through the production of vitamin D in the skin and modulation of immune function. The latter has benefits for skin diseases such as psoriasis and possibly for systemic autoimmune diseases such as multiple sclerosis. The health risks of sun exposure can be mitigated through appropriate sun protection, such as clothing with both good UV-blocking characteristics and adequate skin coverage, sunglasses, shade, and sunscreen. New sunscreen preparations provide protection against a broader spectrum of solar radiation, but it is not clear that this has benefits for health. Gaps in knowledge make it difficult to derive evidence-based sun protection advice that balances the risks and benefits of sun exposure.

The consequences for human health of stratospheric ozone depletion in association with other environmental factors

Ozone depletion, climate and human health.

Comparison of photodermatoses in African-Americans and Caucasians: a follow-up study

BACKGROUND/PURPOSE

Only a few studies have compared frequencies of photodermatoses among different races and skin types. This is an extension of a study performed by Kerr and Lim and evaluates the frequency of photodermatoses in African-Americans compared with Caucasians in the same institution during an 8-year period.

METHODS

Retrospective chart review was performed, including dermatology clinic charts from October 2004 to August 2012 with International Classification of Diseases, Ninth Revision diagnostic codes related to photodermatoses.

RESULTS

We identified 229 patients with photodermatoses. Of these, 138 (46.6%) were African-American and 63 (42.2%) were Caucasian. Statistically significant differences in the distribution of photodermatoses in African-Americans and Caucasians, respectively, were as follows: phototoxic drug eruption (0.7% and 15.9%, P < 0.0001), phytophotodermatitis (0% and 6.3%, P = 0.009), polymorphous light eruption (PMLE) (86.2% and 54%, P < 0.0001) and porphyrias (0% and 7.9%, P = 0.003).

CONCLUSION

Combined with data from Kerr and Lim, this is the largest study of photodermatoses in African-Americans to date. Congruent to former studies, photodermatoses do occur regularly in dark-skinned individuals. Overall, the frequency of photodermatoses in African-Americans and Caucasians are similar; however, PMLE occurs more commonly in African-Americans, and porphyias and phototoxicity occur more commonly in Caucasians.

Actinic prurigo of the lip: Two case reports

Actinic prurigo is a photodermatosis that can affect the skin, conjunctiva and lips. It is caused by an abnormal reaction to sunlight and is more common in high-altitude living people, mainly in indigenous descendants. The diagnosis of actinic prurigo can be challenging, mainly when lip lesions are the only manifestation, which is not a common clinical presentation. The aim of this article is to report two cases of actinic prurigo showing only lip lesions. The patients were Afro-American and were unaware of possible Indian ancestry. Clinical exam, photographs, videoroscopy examination and biopsy were performed, and the diagnosis of actinic prurigo was established. Topical corticosteroid and lip balm with ultraviolet protection were prescribed with excellent results. The relevance of this report is to show that although some patients may not demonstrate the classical clinical presentation of actinic prurigo, the associated clinical and histological exams are determinants for the correct diagnosis and successful treatment of this disease.