Chronic actinic dermatitis

Comparison of Demographic and Photobiological Features of Chronic Actinic Dermatitis in Patients With Lighter vs Darker Skin Types

Importance

Chronic actinic dermatitis (CAD) is classically described in older, white men, although increasing reports describe younger patients with darker skin types, particularly South Asians. Photocontact allergy occurs in CAD but is less studied than contact allergy in this exquisitely photosensitive condition.

Objective

To evaluate for differences in demographic and photobiological features between persons with darker and lighter skin types who have CAD.

Design, Setting, and Participants

This retrospective review included 70 consecutive adult patients (≥18 years) undergoing investigation for photosensitivity who were diagnosed with CAD from November 1, 2000, through August 31, 2015, at the specialist Photobiology Unit of a tertiary academic referral center.

Main Outcomes and Measures

Patient age, sex, ethnicity, clinical features, and phototesting outcomes.

Results

A total of 70 patients (37 men [53%] and 33 women [47%]; mean [SD] age, 50.9 [2.3] years) were diagnosed with CAD. Of these, 36 were non-Hispanic and non-Latino white, 31 were Asian (including 24 South Asian, 4 East Asian, and 3 Middle Eastern), and 3 were black. Patients were aged 9 to 83 years at diagnosis, with a mean (SD) age at onset of 42.6 (2.4) years and duration of disease of 8.8 (1.3) years. Forty-one had lighter skin types (Fitzpatrick skin types I-IV), and 29 had darker skin types (Fitzpatrick skin types V and VI). Patients with darker skin types and CAD were younger at diagnosis (mean [SD] age, 40.7 [3.5] vs 58.1 [2.5] years; P < . 001) and had earlier onset of photosensitivity (mean [SD] age, 35.5 [3.9] vs 47.5 [2.9] years; P = .01) compared with patients with lighter skin types. Of note, the male to female ratio in the lighter skin group was 2:1 compared with 1:2 in the darker skin group. Phototest reactions were equally severe in Fitzpatrick skin types V to VI and I to IV, with minimal erythemal doses to monochromatic UV-B, UV-A, and visible radiation and broadband provocation testing showing similar results. Photoallergic contact reactions to UV filters, personal sunscreen products, and nonsteroidal anti-inflammatory drugs were seen in both groups; 14 of 61 patients (23%) undergoing photopatch testing showed positive photopatch reactions.

Conclusions and Relevance

Chronic actinic dermatitis presents with an earlier age at onset and an inverted male to female ratio in patients with darker compared with lighter skin types. Clinicians should thus be cognizant of CAD in younger women with darker skin types. Photopatch testing should be considered in patients with CAD, with coexistent photocontact allergy occurring in a substantial proportion.

The Successful Use of Topical Tacrolimus Treatment for a Chronic Actinic Dermatitis Patient with Complications of Idiopathic Leukopenia

Chronic actinic dermatitis (CAD) is a photosensitivity disorder marked by severe eczematous lesions on exposed areas. Although associations with contact dermatitis, atopic dermatitis, and human immunodeficiency virus (HIV) have been suggested, its pathogenesis remains unknown. CAD is often refractory, and systemic administration of cyclosporin A has been the treatment of choice. Recently, topical tacrolimus therapy has been reported to be effective. We report the efficacy of topical tacrolimus treatment in a CAD patient who also had the complication of idiopathic leukopenia. A phototest showed marked suppression of erythema formation in the skin pre-treated with tacrolimus before UVB radiation but not in the skin treated after the irradiation. Therefore, it is suggested that tacrolimus may prevent UV-B induced erythema by suppressing a very early phase of the inflammatory process in CAD.

Photoimmunology

The discipline that investigates the biologic effects of ultraviolet radiation on the immune system is called photoimmunology. Photoimmunology evolved from an interest in understanding the role of the immune system in skin cancer development and why immunosuppressed organ transplant recipients are at a greatly increased risk for cutaneous neoplasms. In addition to contributing to an understanding of the pathogenesis of nonmelanoma skin cancer, the knowledge acquired about the immunologic effects of ultraviolet radiation exposure has provided an understanding of its role in the pathogenesis of other photodermatologic diseases.

Photodermatoses: environmentally induced conditions with high psychological impact

Photodermatoses are a group of skin disorders caused or exacerbated by ultraviolet and/or visible radiation, which collectively affect a high proportion of the population and substantially affect quality of life (QoL). Our objective was to assess the psychological impact of these conditions. Patients with a range of photodermatoses diagnosed at a specialist investigation centre in the UK completed questionnaires evaluating (i) anxiety and (ii) depression, using the Hospital Anxiety and Depression Scale (HADS), (iii) social anxiety, using the Fear of Negative Evaluation measure (FNE), (iv) coping strategies (brief COPE) and (v) QoL, using the Dermatology Life Quality Index (DLQI). Questionnaires were returned by 185 of 260 patients (71.1% response rate). Mean age was 50.2 years (SD 14.5, range 20-85), 80.3% female. Polymorphic light eruption was the most common diagnosis, followed by photoaggravated eczema, other photoaggravated dermatological conditions and solar urticaria. Across the sample, high percentages, i.e. 23% and 7.9% of individuals, showed scores indicating clinical levels of anxiety and depression, respectively. Facial involvement was a strong indicator for depression (t = 2.7, p < 0.01). In regression analyses psychological factors (particularly depression and adaptive coping) were the principle predictors of QoL, accounting for 17.7% of the variance (F = 7.61, p < 0.01), while clinical variables accounted for an additional 10.1% (F = 8.96, p < 0.01), with number of months/year affected exerting a significant effect (p < 0.01). This study demonstrates the high psychological comorbidity of these conditions; more awareness of this is required, with adoption of a biopsychosocial approach to their management.

Chronic actinic dermatitis with leonine facies and iatrogenic adrenal insufficiency successfully treated with topical tacrolimus

Chronic actinic dermatitis is a chronic photosensitivity disorder characterized by severe eczematous lesions on sun-exposed skin areas. We report a case of chronic actinic dermatitis presenting with leonine facies and secondary adrenal insufficiency, which was successfully treated with topical tacrolimus. The facial lesions dramatically improved after sun avoidance and topical tacrolimus application. After almost 20 years of oral corticosteroid therapy complicated with secondary adrenal insufficiency, we were able to switch treatment from systemic corticosteroids to topical tacrolimus to control the patient's symptoms.

Alpha-methylene-gamma-butyrolactones: versatile skin bioactive natural products

Natural products containing an alpha-methylene-gamma-butyrolactone moiety, mainly of the sesquiterpene type, are widely observed in plants, which upon coming into contact with skin, will induce major skin toxicological side effects or phytodermatitis. Indeed two main dermatological pathologies have been associated with a skin exposure to molecules containing an alpha-methylene-gamma-butyrolactone moiety: allergic contact dermatitis (ACD) and chronic actinic dermatitis (CAD). ACD is an immunologically based disease resulting from modifications of epidermal proteins by sensitizers or haptens. Indeed, alpha-methylene-gamma-butyrolactones are highly electrophilic structures that can act as Michael acceptors towards nucleophilic residues of proteins. Cysteine and lysine are the most modified residues leading, in the case of enantiomerically pure lactones, to the formation of diastereomeric adducts. This chemical enantioselectivity induces an enantiospecificity of the allergic reaction, i.e., an individual sensitized to one enantiomer will not develop clinical symptoms when exposed to the other enantiomer and vice versa. Sesquiterpene lactones have been also associated with another pathology that involves UV irradiation and DNA modifications. Interestingly, it was found that alpha-methylene-gamma-butyrolactones, in addition to their electrophilic properties, were highly photoreactive molecules able to react with thymine/thymidine to form [2 + 2] photoadducts in very high yields. In all cases a syn regioselectivity was observed, probably associated with the polarization of the exomethylenic bond. This high photoreactivity of alpha-methylene-gamma-butyrolactones towards thymidine could be an explanation of the progressive evolution of allergic contact dermatitis towards chronic actinic dermatitis.

Photodermatoses with onset in the elderly

Photodermatoses are a group of skin disorders induced by ultraviolet radiation (UVR) and, in some cases, visible light. To establish a diagnosis it is important to carefully take a history, physical examination and perform phototesting as well as other testing when appropriate (patch and photopatch tests, antinuclear antibodies, porphyrin profile). This article focuses on the photodermatoses that affect the elderly, which with the ageing of population, particularly in the industrialized societies, are becoming an increasingly important group for the healthcare systems. The most common photodermatoses with onset in the elderly are chronic actinic dermatitis and drug induced photosensitivity.

Throwing a light on photosensitivity in atopic dermatitis: a retrospective study

BACKGROUND

Photosensitivity in atopic dermatitis (AD) is a well known but ill-defined phenomenon.

OBJECTIVES

To determine the prevalence of photosensitivity in patients with AD, define its clinical characteristics, and analyze the photo provocation test (phototest) results.

METHODS

A retrospective study of patients with AD who were phototested because of suspected photosensitivity at our department during the period 1994-2004.

RESULTS

The total number of patients with AD seen in our department between 1994 and 2004 was 3804, of whom 145 patients (45 men and 100 women) were phototested. Photosensitivity was confirmed in 108 (74%) of these 145 patients (33 men and 75 women). The minimal erythema dose (MED) for UVB was decreased in eight of these 108 patients (7%) and the MED for UVA in five patients (5%). Two major clinical reaction patterns were observed: a polymorphic light eruption-type reaction in 51 patients (47%) and an eczematous reaction in 44 patients (41%). Seventy-two of the 108 patients (67%) had a pathologic reaction to UVA and UVB, 18 patients (17%) were only UVB sensitive, and 18 patients (17%) were only UVA sensitive. Photopatch tests were performed in 125 patients (86%). Twenty-nine patients (23%) had a positive photocontact reaction to one or more substances.

CONCLUSION

Photosensitivity is found in approximately 3% of patients with AD and the majority are female. Photosensitivity in patients with AD consists of two clinical reaction patterns distinguishable by phototesting. Patients were diagnosed with either AD and co-existing polymorphic light eruption or photosensitive AD.

[Chronic actinic dermatitis: treatment with topical tacrolimus (two cases)]

BACKGROUND

Chronic actinic dermatitis is usually controlled under systemic immunosuppressive drugs. We report herein two patients successfully treated with topical tacrolimus.

CASE REPORTS

Two men aged 60 and 70 years were treated for chronic actinic dermatitis for two years using systemic immunosuppressive drugs. Due to drug intolerance and treatment resistance, systemic treatment was substituted by topical tacrolimus. Cutaneous lesions improved dramatically within two months but withdrawal of daily application was immediately followed by recurrence of the lesions.

DISCUSSION

Our cases, together with the 10 others reported in the literature, confirm the efficacy of topical tacrolimus in the treatment of chronic actinic dermatitis. Since tacrolimus chiefly targets activated T lymphocytes, it has been successfully deployed in various inflammatory dermatoses and its use is logical in the treatment of chronic actinic dermatitis. While dramatic improvement is achieved within a few weeks in this indication with twice-daily applications of tacrolimus ointment 0.1%, symptoms recur rapidly on dosage reduction, and extremely long-term, or even lifelong, treatment is thus probably needed. Topical tacrolimus application has been shown to be safe for periods of three years. However, the peculiar mechanism of chronic actinic dermatitis with a pronounced imbalance in T-cell subsets raises the question of theoretical risk of carcinogenicity of tacrolimus applications, and this, together with the prolonged duration of treatment, calls for long-term follow-up of chronic actinic dermatitis patients.

Azathioprine in dermatology: The past, the present, and the future

For several decades, dermatologists have utilized azathioprine to treat numerous debilitating skin diseases. This synthetic purine analog is derived from 6-mercaptopurine. It is thought to act by disrupting nucleic acid synthesis and has recently been found to interfere with T-cell activation. The most recognized uses of azathioprine in dermatology are for immunobullous diseases, generalized eczematous disorders, and photodermatoses. In this comprehensive review, the authors present recent advancements in the understanding of azathioprine and address aspects not covered in prior reviews. They (1) summarize the history of azathioprine; (2) discuss metabolism, integrating information from recent publications; (3) review the mechanism of action with attention paid to the activities of azathioprine not mediated by its 6-mercaptopurine metabolites and review new data about inhibition by azathioprine of the CD28 signal transduction pathway; (4) thoroughly examine thiopurine s-methyltransferase genetics, its clinical relevance, and interethnic variations; (5) review prior uses of azathioprine in the field of dermatology and grade the level of evidence; (6) discuss the use of azathioprine in pregnancy and pediatrics; review (7) key drug interactions and (8) adverse effects; (9) suggest a dosing and monitoring approach different from prior recommendations; and (10) explore the future of azathioprine, focusing on laboratory considerations and therapeutic application.

Evolution of clinical pattern of parthenium dermatitis: a study of 74 cases

Our aim was to study the evolution of clinical pattern of parthenium dermatitis. Patients with clinical picture consistent with parthenium dermatitis for 3 years or more along with positive patch test to parthenium were studied. Patients were questioned regarding the site(s) of dermatitis at the onset and change in localization in the following years. Patients were classified into airborne contact dermatitis, chronic actinic dermatitis (CAD) pattern or mixed pattern dermatitis. There were 74 patients (49 men and 25 women) with an age range of 22-70 years and the mean duration of 7.7 years. 60 (39 men and 21 women) patients had airborne contact dermatitis, 5 mixed pattern and 9 CAD pattern at the onset. Of the 60 patients with airborne contact dermatitis, 27 (19 men and 8 women) changed to CAD pattern and 11 (6 men and 5 women) to mixed pattern after an average period of 4.2 years. Of the 19 patients photopatch-tested with parthenium, 3 showed photoallergic reaction and the other 3 showed photoaggravation. Our results suggest that the clinical pattern of parthenium dermatitis undergoes a significant change after the onset, i.e. progresses from airborne contact dermatitis to mixed pattern or CAD pattern.

Chronic actinic dermatitis in the elderly: recognition and treatment

Chronic actinic dermatitis is a condition involving abnormal cutaneous photosensitivity to UV and, often, visible wavelengths. It is rare, but more common in the elderly than in younger populations, with an estimated prevalence of one in 2000 in the > or = 75-year-old population in Tayside, Dundee, Scotland. It usually presents as a dermatitis that maximally, but not exclusively, affects photo-exposed skin. Investigation to confirm the diagnosis and guide management includes phototesting and patch testing. The mainstay of treatment is education about the condition and advice on sunlight and allergen avoidance. Topical corticosteroids and emollients are always required, at least intermittently, and it is sometimes necessary to resort to systemic immunosuppression, usually with corticosteroids or azathioprine.

Implication for photosensitive patients of ultraviolet A exposure in vehicles

BACKGROUND

Photosensitive patients sometimes report disease flares during journeys by car. Window glass blocks all UVB but not all UVA. All car windscreens are made from laminated glass. Side and rear windows are usually made of nonlaminated glass.

OBJECTIVES

To determine which types of glass provide most protection from UVA with particular reference to the implications for patients with polymorphic light eruption (PLE).

METHODS

The percentage transmission of UVA was determined for a selection of glass, both laminated and nonlaminated, and with differing colour tints.

RESULTS

Laminated glass transmits less UVA than nonlaminated glass. Tinted glass transmits less UVA than clear glass. Nonlaminated clear glass transmitted the highest percentage of UVA (62.8%) and grey laminated glass the lowest (0.9%). A dose of 5 J cm(-2) UVA, enough to trigger PLE in some patients, could be transmitted through clear nonlaminated glass in 30 min but would take 50 h through grey laminated glass.

CONCLUSION

Patients with severe UVA-induced PLE and other photosensitivity disorders may have disease flares from solar UVA transmission through side-window glass. Protective measures such as wearing long-sleeved clothing, keeping the arm beneath the bottom of the window aperture, or choosing tinted and laminated car windows may be helpful.

Chronic actinic dermatitis: A retrospective analysis of 44 cases referred to an Australian photobiology clinic

A retrospective study was performed to analyse the clinical and photobiological features and therapeutic outcomes of 44 patients with chronic actinic dermatitis who were evaluated over an 8.3-year period. The study population comprised 37 men and seven women with a mean age of 62.7 years (range 26-85 years). The most common abnormal phototest results were decreased minimal erythema doses to both UVA and -B (73.8%), and to UVA alone (14.3%). Twenty-six patients (78.8%) had at least one allergic, photoallergic or combined allergic/photoallergic reaction. A total of 139 positive contact or photocontact reactions were recorded (mean 4.2 per patient). Most commonly, treatment consisted of photoprotection, topical corticosteroids and episodic use of systemic agents, in particular azathioprine.

Classification and evaluation of photodermatoses

Photodermatoses can be classified into five general categories: 1) idiopathic photodermatoses, including polymorphic light eruption (PMLE), actinic prurigo, hyroa vacciniforme, chronic actinic dermatitis, and solar urticaria; 2) photodermatoses which are secondary to exogenous agents, including phototoxic and photoallergic reactions; 3) photodermatoses secondary to endogenous agents, mainly the porphyrias; 4) photoexacerbated dermatoses, including autoimmune disease, infectious conditions, and nutritional deficiencies; and 5) genodermatoses. The initial step in evaluating a photosensitive patient is based on a directed personal and family history. The morphology of the eruption, phototests, and in some patients, photopatch tests are essential in focusing the diagnosis. Skin biopsies and laboratory investigations, such as antinuclear antibody (ANA) panels and porphyrin profiles, may be required to further confirm the diagnosis.

Diagnosis and treatment of chronic actinic dermatitis

Chronic actinic dermatitis, synonymous with the photosensitivity dermatitis and actinic reticuloid syndrome, presents as a dermatitis and/or a pseudolymphomatous eruption. Abnormal photosensitivity to ultraviolet (UV) and often visible radiation is a feature. Many patients also have multiple contact allergens. Histopathologic features vary, with a spectrum from mild dermatitis to pseudolymphomatous (reticuloid) features. The essential tests to make the diagnosis and to guide advice on avoidance of the responsible wavelengths and any contact allergens are phototesting and patch testing. Chronic actinic dermatitis can be regarded as a disorder of increased susceptibility, for reasons that remain uncertain, to develop delayed-type allergic responses to both endogenous photoallergens and exogenous allergens. Treatment consists of detailed advice on sunlight and allergen avoidance (guided by the results of investigations), topical corticosteroids, and emollients. When these measures are insufficient alone, systemic immunosuppressives may be considered: systemic prednisolone for acute exacerbations or azathioprine if systemic treatment is required for more than a few weeks.

Spectrum of idiopathic photodermatoses in a Mediterranean country

BACKGROUND

Idiopathic photodermatoses are considered to be common disorders in the population of northern latitude countries, presumably because of the dominance of more "sun-sensitive" individuals with a light-skinned complexion. The incidence of these disorders in the Mediterranean or tropical countries is often under-appreciated because of the higher degree of perennial presence of sunlight and the prevalence of darker skin-type individuals who are seemingly more resistant to the development of sun sensitivity.

METHODS

We performed a retrospective, chart-based review of all patients who were diagnosed with idiopathic photodermatoses at a photodermatology referral center in Athens, Greece, during a period of 10 years. Our aim was to assess the pattern of idiopathic photosensitivity disorders in a Mediterranean country and to determine their epidemiological, clinical, and photobiological profile.

RESULTS

A total of 310 patients were referred to our center with symptoms of photosensitivity. One hundred and forty-six patients (47.0%) were diagnosed with an idiopathic photosensitivity disorder by means of history, clinical examination, biochemical screening, histology, and phototesting. The most prevalent disorder was polymorphous light eruption, which was diagnosed in 95 patients (65.0%) of our cohort. Chronic actinic dermatitis occurred in 15 patients (10.2%), solar urticaria in 26 patients (17.8%), actinic prurigo in three patients (2.0%), hydroa vacciniforme in one patient (0.6%) and juvenile spring eruption in six patients (4.1%).

CONCLUSIONS

Compared with the results of other studies, the prevalence of idiopathic photodermatoses appears to have a similar trend to that of higher latitude countries. Distinct features in our series include the higher incidence of idiopathic photosensitivity in patients with a fair-skinned complexion (skin types II-III) and the frequent appearance of photo-induced eruptions during sunny weather breaks in the winter period.

The idiopathic photodermatoses

The idiopathic photodermatoses present a challenge for dermatologists. Although, as in other specialty areas, the classical clinical presentation produces few problems, it is the severe forms and overlap cases that cause the most difficulty. It is fortunate that the semi-objective investigation of phototesting is available, which, when conducted carefully, reveals so much about the nature of this group of conditions. This essential investigation not only helps achieve a diagnosis, but also affords material for study and a means of monitoring therapy response or progress towards spontaneous resolution. Although these conditions are grouped together, throughout this century we have seen a continuing process of distinct diseases emerging as a consequence of careful clinical observation and investigation.

Contact and photocontact sensitivity to sunscreens. Review of a 15-year experience and of the literature

This review summarizes published and unpublished data of our 15-year experience with sunscreen allergy and photoallergy. From 1981-1996, 402 patients with suspected clinical photosensitivity were patch and photopatch tested with the commercial sunscreens and facial cosmetics that they had used and with chemical UV absorbers, fragrance materials, preservatives, and emollients. 80 patients (20%) (28 men, 52 women) demonstrated allergic and/or photoallergic contact dermatitis to 1 or more UV absorber(s). In 47 patients with photodermatoses or photo-aggravated dermatoses and in 33 subjects with normal photosensitivity, 91 allergic and 84 photoallergic reactions to UV filters were observed. Over the years sunscreens were added to the test series, which since 1989 comprised the following 10 UV absorbers and which induced allergic (a) and photoallergic (pa) reactions (number, type of reaction): 4 UVA absorbers--isopropyldibenzoylmethane (30a/32pa); butyl methoxydibenzoyl-methane (15a/13pa); benzophenone-3 (3a/9pa); benzophenone-4 (0a/0pa); and 6 UVB absorbers--PABA (2a/2pa); octyl dimethyl PABA (1a/2pa); methylbenzylidene camphor (32a/5pa); octyl methoxycinnamate (3a/4pa); isoamyl p-methoxycinnamate (4a/10pa); and phenylbenzimidazole sulfonic acid (1a/7pa). The frequent (photo)sensitization to isopropyldibenzoylmethane was the reason that its production was discontinued in 1993. 47 patients reacted to fragrance materials, 11 to preservatives and 2 to lanolin alcohol. These constituents were contained in the commercial sunscreens and cosmetics that they had used. Continuous revision of the UV absorber photopatch test series was necessary to be closer to the real frequency of exposure and of reported (photo)allergy to newer sunscreens. Clinicians should consider contact and photocontact allergy, especially in patients with photodermatoses and photo-aggravated dermatoses, and they should perform photopatch testing. Once the culprit has been identified, its INCI (International Nomenclature Cosmetic Ingredients) designation should be given to the patient, who must be warned to avoid products containing the (photo)allergen.

Olaquindox-induced airborne photoallergic contact dermatitis followed by transient or persistent light reactions in 15 pig breeders

There have been no previous reports of photosensitivity following photoallergy to airborne olaquindox in a large group. 15 pig breeders, with photo-distributed dermatitis related to olaquindox dust, were investigated to study the nature, promoting factors, and course of this disease. Minimal erythema doses for UVA and UVB were established before photopatch testing and at intervals thereafter. All patients presented with olaquindox-induced photoallergy. In 14 cases, this was followed by prolonged increased sensitivity to UVA. 7 patients also displayed an increased sensitivity to UVB. 13 farmers came into contact with olaquindox in mineral feed (1000 mg/kg) and only 2 in final feed (50 mg/kg). 8 patients avoided further contact with olaquindox because of warnings in the media. Allergies and photoallergies to other occupational substances preceded or followed olaquindox (photo)allergy. Because of their increased sensitivity to light, most of these farmers used sunscreens, and 2 of them developed (photo)allergy to UV-absorbers. As a result of our studies, we recommend photopatch testing for olaquindox in pig breeders with photo-distributed dermatitis. This would enable the early recognition of photoallergy to olaquindox and the prevention of persistent light reaction.

Photodermatoses in a Singapore skin referral centre

The inducing or exacerbating effect of sunlight on skin diseases is often not appreciated in tropical countries, perhaps because of the perennial presence of sunlight, and a retrospective review of photodermatoses seen in a referral skin clinic was therefore carried out. The photodermatoses seen were secondary photoaggravation of primary skin diseases (32.2%), systemic drug photosensitivity (11.3%), polymorphic light eruption (13%), chronic actinic dermatitis (5.3%), solar urticaria (5.3%), actinic prurigo (4%), photoallergic contact dermatitis (2.6%), porphyria (1.3%) and xeroderma pigmentosum (1.3%). Compared with the results of Western studies, there were more photoaggravated underlying skin diseases and systemic drug photosensitivity, and fewer idiopathic photodermatoses and photoallergic contact dermatitis; the common photoallergens were chlorpromazine, promethazine and musk ambrette, very similar to those seen in the West.

Two cases of mequitazine-induced photosensitivity reactions

Mequitazine is a phenothiazine derivative antihistamine. We experienced 2 cases of mequitazine-induced photosensitivity reaction in patients who took mequitazine for their dermatologic problems. Case no. 1 showed features of photoallergy such as 1-month incubation period, decreased MED to UVA, strong positive photopatch test result, cross reaction to chlorpromazine, and angry back phenomenon found in allergic contact dermatitis. In addition, an immediate erythematous macule was observed on the photopatch test site of mequitazine directly after UV exposure which was similar to the immediate erythema noted in chlorpromazine photoallergy. During the follow-up period of two months, there was transiently decreased MED to UVB, which became normalized after 1 month treatment with cyclophosphamide. In case no. 2, the pathogenic mechanism seemed to be persistent light reaction preceded by systemic photoallergy, as he had taken mequitazine for 6 months, and there were strong positive photopatch test results with immediate erythema reaction, cross-reaction to promethazine, decreased MED to both UVA and UVB, and persistence of the photosensitivity over a 3-year follow-up period after discontinuation of the mequitazine. Photopatch tests to 1% mequitazine with 5 J/cm2 of UVA in 30 normal subjects were all negative, which means that 1% concentration may be appropriate for the photopatch test. Mequitazine seemed to play a part similar to chlorpromazine, and absence of mequitazine-induced photosensitivity may be due to a relatively low dosage of the drug. However, dermatologists should be cautious about a photosensitivity reaction induced by mequitazine or other phenothiazine-derivative drugs.

Photochemotherapy beyond psoriasis

Photochemotherapy involves the therapeutic use of nonionizing radiation in combination with a photosensitizing chemical to trigger a photochemical reaction that mediates a beneficial effect. The successful introduction and widespread use of psoralen photochemotherapy (PUVA) in the management of psoriasis was the chief stimulus for recent interest in the therapeutic use of nonionizing radiation in various other dermatoses. This article discusses the expanding spectrum of diseases responding to PUVA therapy. More than 30 conditions such as atopic dermatitis, mycosis fungoides, vitiligo, the photodermatoses, chronic graft-versus-host disease, and granuloma annulare have been successfully treated with oral psoralen photochemotherapy. Various mechanisms of response to treatment are discussed including photoimmunologic effects, selective cytotoxicity, alterations of cell function, and stimulation of melanocytes. Finally, the limitations to the use of PUVA therapy are identified and its future use in other cutaneous and systemic diseases are discussed.

Cellular sensitivity to oxidative stress in the photosensitivity dermatitis/actinic reticuloid syndrome

Skin fibroblasts from certain patients with the photosensitivity dermatitis/actinic reticuloid syndrome show enhanced sensitivity to ultraviolet radiation compared to normal fibroblasts. To probe further the link between oxidative damage and this disease, we have obtained a more extensive set of cell lines from patients with a severe form of the disease and examined their sensitivity towards oxidative stress by measuring cell survival following UVA radiation (330-450 nm) or hydrogen peroxide treatment (0.1-2.4 mM). The activation of the stress gene, heme oxygenase, has also been assessed by measuring the accumulation of mRNA after hydrogen peroxide treatment. Our studies have confirmed that a slight ultraviolet sensitivity is a characteristic of photosensitivity dermatitis/actinic reticuloid syndrome cell strains and we further demonstrate that these cell lines are particularly sensitive to hydrogen peroxide with up to a three- to fourfold increased sensitivity as compared to normal controls. We also show that certain ataxia telangiectasia strains that are especially sensitive to hydrogen peroxide are also slightly sensitive to ultraviolet radiation. Hydrogen peroxide induces accumulation of mRNA for the oxidant-inducible stress protein, heme oxygenase, with similar kinetics (maximum mRNA accumulation 2-4 h following treatment) and with a similar range of magnitudes in both normal (6.6-20.6 times mRNA increase over basal levels) and photosensitivity dermatitis/actinic reticuloid (2.9-12.8 times) skin cells. Because cells from photosensitivity dermatitis/actinic reticuloid patients show increased sensitivity towards oxidative stress but show no significant change in oxidant activation of the heme oxygenase gene, we propose that the defect involves a late stage of processing of oxidative damage rather than a compromised free radical scavenging system.

1992 AAD Award for Excellence in Education: The Integrated Basic and Clinical Science Conference Series at the University of Texas Southwestern Medical Center

This article was written to share information concerning the establishment and implementation of a successful, integrated basic and clinical science conference series for resident trainees in dermatology. We discuss the underlying philosophy and describe the concepts employed in, and the dynamics that have resulted from, this educational experiment. Finally, we include the schedule and references for the 1993-1994 academic year.