Immunologically mediated photodermatoses: diagnosis and treatment

Actinic conjunctivitis and its relationship with prurigo in an indigenous population from the Highlands of Chiapas, Mexico

PURPOSE

Actinic conjunctivitis (AC), along with cheilitis (AChe), is part of the clinical spectrum of actinic prurigo (AP), a rare photo dermatosis that affects high-risk populations. We analyzed the clinical manifestations and onset of actinic conjunctivitis (AC), and its relationship with prurigo (AP) in a susceptible population.

METHODS

This prospective observational cohort study was performed on Indigenous populations from the highlands of Chiapas, Mexico. Thorough dermatological and ophthalmological examinations were performed in patients attending a primary health care center. The clinical features, labor and environmental factors, onset timing, and clinical staging of AC and AP were analyzed.

RESULTS

Of the 2913 patients studied, 54 patients (108 eyes) (1.8%) had AC, and 14 patients (25.9%) had AP. The mean age at diagnosis was 36.18 ± 18.52 years (6-70 years). The mean residential altitude was 1884 ± 434.2 m above sea level. Mean self-reported sun exposure was 5.14 ± 3.1 h a day (0.5-12 h). A total of 90.7% reported exposure to biomass fuels during cooking, and 50% to farm animals. AC was the sole manifestation in 70% of the cases. All patients had nasal and temporal photo-exposed conjunctiva. Among the eyes, 12.9% were classified as stage-1, 64.8% as stage-2, and 22.2% stage-3. A total of 83.3% of the patients had hyperpigmented lesions, and 35.1% had evaporative dry eye disease.

CONCLUSIONS

AC may be the initial or sole manifestation of AP. Most AC cases (87%) were initially observed at the advanced stages of the disease. Although solar exposure was not associated with late AC stages, a positive association was found with farm animal exposure. Evaporative dry eye associated with meibomian gland dysfunction has not been previously reported in patients with AC.

Chronic actinic dermatitis: A 5-year clinical analysis of 488 patients in China

BACKGROUND/PURPOSE

Chronic actinic dermatitis (CAD) is a spectrum of diseases with chronic photosensitivity occurring mostly among middle-aged and older men. We seek to explore the characteristics and pathogenesis of CAD among the Chinese population.

METHODS

The medical records of 488 CAD cases diagnosed by phototesting at Huashan Hospital, Fudan University from January 2014 to December 2018 were analyzed retrospectively.

RESULTS

Among the 488 patients, 344 were male and 144 were female. 84.8% of the cases were over 40 years old at the age of onset, while the remaining with an early age of onset had a prevalence of atopic history of 21.6%. Up to 45.0% of the patients reported excessive sun exposure and outdoor activities before the initiation of symptoms. The typical skin lesions were erythema, papules and plaques laid predominantly in sun-exposed areas. 42.8% of the cases showed sensitivity to UVB only, 20.7% were both sensitive to UVA and UVB, and 18.2% had UVA sensitivity only. The most predominant photoallergens were chlorpromazine (80.1%), thimerosal (17.2%), potassium dichromate (12.7%), etc. The most prevalent patch test allergens were potassium dichromate (24.4%), thimerosal (20.5%), formaldehyde (16.8%), etc. CONCLUSIONS: CAD was more commonly seen in males over 40 years old. The action spectrum of Chinese patients is primarily in the UVB range. Exposure to excessive sunlight or contact allergens and photoallergens are important risk factors. Photobiology tests are essential in detecting photosensitivity and recognizing potential photosensitizers. Early avoidance of confirmed photoallergens and sun exposure may prevent photosensitive reactions from progressing into persistent photosensitivity.

Long-wavelength ultraviolet A (UVA-1) phototherapy for the treatment of patients with atopic dermatitis

One of the methods of therapy for atopic dermatitis is long-wavelength ultraviolet therapy A (UVA-1- therapy). This review aims to provide the mechanisms of action of UVA-1-therapy an overview about the effectiveness of UVA-1-therapy in patients with atopic dermatitis taking into account factors that can affect the effectiveness of treatment radiation dose, skin phototype of patients, concomitant drug therapy. The available data on a decrease in the severity of atopic dermatitis as a result of the course of UVA-1-therapy and on a decrease in the severity of itching in patients are presented. The data on the rate of onset of the therapeutic effect of UVA-1-therapy and the duration of its maintenance are considered. The safety of UVA-1-therapy is discussed, and the most frequent undesirable effects a feeling of warmth, fever, itching, hyperpigmentation, are given. The possibility of developing side effects requiring discontinuation of treatment is assessed. The data obtained indicate the effectiveness and safety of the UFA-1-radiation in the treatment of patients with moderate-to-severe atopic dermatitis.

Pathogenesis of solar urticaria: Classic perspectives and emerging concepts

Solar urticaria is a rare, immunologically mediated photodermatosis in which activation of cutaneous mast cells is triggered by specific wavelengths of solar electromagnetic radiation. This manifests clinically as the rapid development of cutaneous itch, erythema and wheal formation after several minutes of sun exposure. Disease mechanisms in solar urticaria remain incompletely elucidated and there have been few recent investigations of its pathobiology. Historic passive transfer experiments performed during the twentieth century provide support for a 'photoallergy' model of disease pathogenesis, wherein molecular alteration of a putative chromophore by solar electromagnetic radiation produces mast cell activation via an IgE-dependent mechanism. However, this model does not account for several observations made during passive transfer experiments nor does it explain a range of subsequent clinical and photobiological observations made in solar urticaria patients. Furthermore, increased understanding of the molecular dynamics underpinning cutaneous mast cell responses highlights the need to reformulate our understanding of solar urticaria pathogenesis in the context of this contemporary scientific landscape. In this review, we discuss the current understanding of solar urticaria pathogenesis and, by incorporating recent scientific and clinical observations, develop new hypotheses to drive future investigation into this intriguing disorder.

Ultraviolet A rush hardening for chronic actinic dermatitis: Pilot treatment outcomes

Chronic actinic dermatitis (CAD) is a common debilitating photodermatosis. Patients often have to completely avoid outdoor activities, which severely impacts their quality of life. Phototherapy is effective for CAD and seems to increase patients' tolerance towards sunlight and consequently decrease the extent of disease. Unfortunately, the slower onset and time-consuming nature of phototherapy limits the clinical application. Considering the effectiveness and time-saving nature of ultraviolet (UV)-A rush hardening in solar urticaria, we performed a pilot study to determine whether UV-A rush hardening is effective in CAD. Six patients with CAD were exposed to multiple sessions of UV-A for 4-5 days at 1-h intervals/day. Subsequently, maintenance UV-A exposure was performed at 1-2-week intervals. Phototesting at baseline showed that three patients were sensitive to both UV-A and -B, and the other three patients only showed UV-A sensitivity. All of the patients responded well to UV-A rush hardening and four (67%) maintained a good remission status after 1 year. The results of this pilot study suggest that UV-A rush hardening phototherapy is effective and well tolerated in the treatment of CAD, while future larger prospective studies using objective scores of disease activity and quality of life are needed.

Utilizing UVA-1 Phototherapy

There is a long history of utilization of phototherapy for treatment of skin conditions. Because of its longer wavelength, UVA1 phototherapy is able to penetrate into the dermis and subcutis. This depth of penetration, combined with its unique immunomodulating properties, makes UVA1 an effective treatment modality for many immune-mediated skin diseases. In some cases, it performs better than other types of phototherapy.

Primary Cutaneous CD30+ Anaplastic Large T Cell Lymphoma in a Patient Treated with Cyclosporine for Actinic Reticuloid

Actinic reticuloid (AR)-a subtype of chronic actinic dermatitis-clinically and histopathologically shows lymphoma-like features. We report a male patient initially diagnosed with erythrodermic cutaneous T cell lymphoma (CTCL) who developed severe broadband photosensitivity. Clinical evaluation, histopathology, and phototesting were consistent with AR. The patient was treated with cyclosporine 150-300 mg/d. Under this therapy, he developed several times primary cutaneous anaplastic large cell lymphomas (C-ALCL) which in part tended to regress spontaneously under cyclosporine reduction. The association between cyclosporine treatment and development of C-ALCL and other CD30+ lymphoproliferative disorders has previously been reported in patients with atopic dermatitis, psoriasis, and transplant patients. In conclusion, the present case highlights the difficulties arising in the distinction between AR and CTCL and shows that long-term cyclosporine treatment may cause C-ALCL development in AR as well.

Solar urticaria - An Australian case series of 83 patients

Solar urticaria (SU) is a rare form of urticaria with a pathogenesis that is poorly understood. It affects all skin types, can be difficult to diagnose, and is challenging to manage effectively. We conducted a retrospective review of patients with SU in our institution. A total of 83 patients (56 females) were identified as having SU. The mean age was 32 years (7-74) at first development of symptoms/signs of SU. Pruritus was the most common symptom reported (79%). Of the 60 patients who underwent monochromator testing at least once, 35 had SU confirmed with most reacting to visible light and UVA, or to UVA alone. Antihistamines and sun avoidance remain the mainstay treatment for SU but other treatments, including omalizumab, are of potential interest in treating patients with recalcitrant SU. The characterisation of this large case series of patients may help dermatologists recognise and manage this rare disorder appropriately.

Ultraviolet A1 Phototherapy for Fibrosing Conditions

In this article we describe efficacy and safety aspects of ultraviolet A1 (UV-A1) phototherapy in fibrosing conditions. UV-A1 is a specific phototherapeutic modality that is defined by a selective spectral range (340–400 nm). UV-A1 includes distinct modes of action qualifying this method for therapy of a variety of conditions, in particular fibrosing skin diseases. Concerning efficacy of UV-A1 phototherapy in fibrosing conditions, the best evidence obtained from randomized controlled trials exists for localized scleroderma. Moreover, fibrosing disorders such as lichen sclerosus and graft-vs.-host disease can be treated successfully by means of UV- A1. Regarding the optimal dosage regimen medium-dose UV-A1 seems to be linked to the best benefit/risk ratio. Possible acute adverse events of UV-A1 phototherapy include erythema and provocation of photodermatoses. Skin ageing and skin cancer formation belong to the chronic adverse events that may occur after long-term UV-A1 phototherapy.

Cutaneous Hematolymphoid and Histiocytic Proliferations in Children

This article focuses on cutaneous hematopoietic neoplasms that are more likely to be encountered in the pediatric age-group and includes both lymphoproliferative and histiocytic disorders. The cutaneous hematologic disorders in children have a different epidemiologic profile to what is seen during adulthood. Although mycosis fungoides is the most frequent form of cutaneous lymphoma in adults, it is very rare in children. Because lymphoblastic leukemias and lymphomas are more frequent in the pediatric setting, cutaneous leukemic infiltrates are relatively common in this age-group. Similarly, histiocytic disorders are more common in children, particularly Langerhans cell histiocytosis and juvenile xanthogranuloma. Notably, the histiocytic disorders have undergone significant modifications on their nomenclature in the basis of the molecular characteristics that are present in them. A summary of the most frequent cutaneous hematopoietic disorders in children will be discussed further in this review.

Cutaneous EBV-related lymphoproliferative disorders

This article will focus on the cutaneous lymphoproliferative disorders associated with EBV, with an emphasis on the upcoming changes in the revised 4th Edition of the WHO classification of tumors of the hematopoietic system, many of which deal with cutaneous disorders derived from NK-cells or T-cells. Extranodal NK/T-cell lymphoma usually presents in the upper aerodigestive tract, but can involve the skin secondarily. EBV-associated T- and NK-cell lymphoproliferative disorders (LPD) in the pediatric age group include the systemic diseases, chronic active EBV infection (CAEBV) and systemic EBV+ T-cell lymphoma of childhood. Hydroa vacciniforme (HV)-like LPD is a primarily cutaneous form of CAEBV and encompasses the lesions previously referred to as HV and HV-like lymphoma (HVLL). All the T/NK-cell-EBV-associated diseases occur with higher frequency in Asians, and indigenous populations from Central and South America and Mexico. Among the B-cell EBV-associated LPD two major changes have been introduced in the WHO. The previously designated EBV-positive diffuse large B-cell lymphoma (EBV-DLBCL) of the elderly, has been changed to EBV-DLBCL with 'not otherwise specified' as a modifier (NOS). A new addition to the WHO system is the more recently identified EBV+ mucocutaneous ulcer, which involves skin and mucosal-associated sites.

Actinic prurigo

Actinic prurigo is a chronic photodermatosis with onset in childhood or before 20 years of age. It is most prevalent in Amerindians and Latin American mestizos, although it has been reported worldwide. Patients present with photodistributed, erythematous excoriated papules, cheilitis, and conjunctivitis. There is strong association with human leukocyte antigen DR4, especially the DRB1*0407 subtype. Treatment consists of photoprotection and the use of thalidomide.

Chronic actinic dermatitis

Chronic actinic dermatitis (CAD) is an immunologically mediated photodermatosis characterized by pruritic eczematous and lichenified plaques located predominantly on sun-exposed areas with notable sparing of eyelids, skin folds, and postauricular skin. CAD is thought to be due to secondary photosensitization of an endogenous antigen in the skin. Management of CAD should include strict photoprotection and topical agents, including corticosteroids and calcineurin inhibitors. Other treatments with noted efficacy include oral prednisone, cyclosporine, azathioprine, and mycophenolate mofetil. Photoprotection and avoidance of allergens, if identified, may lead to spontaneous resolution of CAD in 50% of patients over 15 years.

T regulatory cells and related immunoregulatory factors in polymorphic light eruption following ultraviolet A1 challenge

BACKGROUND

Polymorphic light eruption (PLE) is considered to be an autoimmune-mediated skin condition in which the normal ultraviolet (UV)-induced local immunosuppression appears to be absent, leading to recognition of photoinduced autoantigens and subsequent inflammation.

OBJECTIVES

To investigate T regulatory cells (Tregs) and related immunoregulatory factors in PLE lesions and controls.

METHODS

Skin biopsies were performed in 13 patients with UVA1-challenged PLE, 12 female patients with chronic discoid lupus erythematosus (CDLE) and 11 healthy controls who had exposure to UVA1. Immunohistochemistry and four-colour immunofluorescence studies were performed.

RESULTS

Patients with CDLE and UVA1-exposed controls showed significantly decreased epidermal immunoreactivity for CD1a compared with patients with PLE (P = 0·0001). Four-colour immunofluorescence revealed a median percentage of CD4+CD25+FOXP3+ Tregs of 7·6% (range 3·7-13·6%) in PLE, a median of 11·7% (range 9·5-13·9%) in CDLE and a median of 3·4% (range 0-6·8%) in controls. Compared with UVA1-exposed controls, PLE and CDLE lesions showed significantly decreased transforming growth factor (TGF)-β1 immunoreactivity in the epidermis (P = 0·0003). In PLE lesions, we observed significantly decreased interleukin (IL)-10 expression compared with CDLE (P = 0·022). In the dermis, receptor activator of nuclear factor-κB ligand (RANKL) expression was increased in UVA1-exposed controls compared with PLE and CDLE (P = 0·018).

CONCLUSIONS

Similar to CDLE lesions, UVA1-challenged PLE lesions display an altered immunoregulatory network, as indicated by decreased epidermal or dermal expression of TGF-β1, IL-10 and RANKL, and a relatively low number of Tregs, particularly when compared with other inflammatory skin conditions reported in the literature.

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.

Photoprotective effects of methoxycinnamidopropyl polysilsesquioxane

A new sunscreen ingredient, methoxycinnamidopropyl polysilsesquioxane (MCP-PSQ), which contains an UV-absorbing p-methoxycinnamoyl group, has been developed synthetically and evaluated using in vitro and in vivo approaches. Previous studies revealed that MCP-PSQ has a raising or boosting effect on the sun protection factor (SPF) of other sunscreen agents. In this study, we demonstrated that MCP-PSQ, an organic/inorganic hybrid compound, has photoprotective effects for human fibroblasts, and for hairless mouse and human skin. MCP-PSQ increases cell viability and suppresses the expression of p53 protein in fibroblasts after UV exposure. In addition, the numbers of sunburn cells and mast cells are reduced by topical application of MCP-PSQ on hairless mouse skin after UV irradiation. A 10% MCP-PSQ cream has higher and similar effects on SPF values for human skin compared to 5% titanium dioxide (TiO(2)) and 5% ethylhexyl methoxycinnamate (EHMC), respectively. The SPF value obtained using the MCP-PSQ cream did not drop after UV irradiation of the cream itself. However, higher dose of UV irradiation is required to guarantee the stability or photostability of the formulation. Further, there were no side effects such as erythema, edema, itch or tingling, suggesting that MCP-PSQ is a good sunscreen agent.

Photodermatoses: diagnosis and treatment

BACKGROUND

Sunlight induces a wide variety of dermatoses. Their differential diagnosis is problematic not only because of similar phenotypes, but also because of confusing nomenclature and classification.

METHODS

We selectively reviewed the literature of the past 20 years and describe the modern nosology of photodermatoses and their clinical features, diagnosis, and treatment. Readers should be able to provide correct and efficient diagnostic evaluation and treatment of patients with dermatoses induced by ultraviolet radiation.

RESULTS

Photodermatoses are caused by an abnormal reaction to sunlight, usually to its ultraviolet component. They are divided into phototoxic and photoallergic reactions to known photosensitizers and idiopathic photodermatoses, in which the photosensitizer is unknown. Some types are extremely rare, such as hydroa vacciniforme (prevalence 0.34 per 100,000), while others are very common, such as polymorphic light eruption (prevalence 10% to 20%).

CONCLUSION

Photodermatoses are not life-threatening but can cause considerable suffering. Prevention is just as important as treatment.