Shedding a light on the importance of photopatch testing: A 12-year experience in a dermatology unit.

BACKGROUND: Photopatch testing has been standardized for diagnosing photoallergic contact dermatitis but is still infrequently used. OBJECTIVES: To characterize photopatch test (PPT) results and their clinical relevance. METHODS: We collected retrospective data from patients photopatch tested in our Dermatology Unit (2010-2021), using the European PPT 'baseline' series, other allergens, and patient's own products, when appropriate. RESULTS: Out of 223 patients, 75 patients (33.6%) were reactive with 124 positive PPT reactions, considered relevant in 56/223 patients (25.1%) and in 72/124 reactions (58.1%). Most reactions were caused by topical drugs (n = 33; 45.8%), such as ketoprofen or promethazine, and 7 (9.8%) by systemic drugs, such as hydrochlorothiazide and fenofibrate. 'Classical' ultraviolet filters were responsible for six positive PPT reactions whereas there was only three relevant PPT to the 'newer' UV filters. Patients' sunscreens/cosmetics or plant extracts caused 10 positive PPT each. Additional patch test reactions were observed, mostly to Tinosorb® M. CONCLUSION: Contrary to the trend in ACD, most positive PPT reactions were caused by topical drugs, outweighing ultraviolet filters and cosmetics. We stress the low reactivity to the 'newer' UV filters included in the PPT series. PPT was occasionally positive in systemic drug photosensitivity, but overall PPT reactivity was low.

[Phototoxic and photoallergic reactions]. / Phototoxische und photoallergische reaktionen.

Many artificial or naturally occurring substances are included under the term photosensitizer. After ultraviolet (UV) exposure such agents can lead to increased photosensitivity and subsequently to phototoxic or photoallergic reactions in the skin. From clinical observations and comprehensive studies typical reaction patterns can be deduced which can clarify the difference between phototoxic and photoallergic dermatitis.An illuminated epicutaneous test based on conventional epicutaneous tests, the photopatch test, was developed as a screening method for identification of photosensitizers. The diagnostic specificity and sensitivity of the test is comparable to conventional epicutaneous testing. If possible photosensitizers do not cause any relevant reactions with the photopatch test, other test procedures, such as the photoprick, photoscratch and illuminated intracutaneous tests are available. If the actual photosensitizer is not the test substance but a metabolite of the test substance, a systemic photoprovocation test can be indicated.

Skin hardening effect in patients with polymorphic light eruption: comparison of UVB hardening in hospital with a novel home UV-hardening device.

BACKGROUND: An effective prophylactic treatment of patients with polymorphic light eruption (PLE) consists of repeated low, gradually increasing exposures to UVB radiation. This so-called UV(B) hardening induces better tolerance of the skin to sunlight. OBJECTIVE: SunshowerMedical company (Amsterdam) has developed an UV (B) source that can be used during taking shower. The low UV fluence of this apparatus makes it an interesting device for UV hardening. In a group of PLE patients, we compared the effectiveness of the irradiation with SunshowerMedical at home with that of the UVB treatment in the hospital. METHODS: The PLE patients were randomized for one of the treatments. The hospital treatment consisted of irradiations with broad-band UVB (Waldmann 85/UV21 lamps) twice a week during 6 weeks. The home UV-device was used each day with the maximal irradiation time of 6 min. The outcome assessment was based on the information obtained from patients' dermatological quality of life (DLQI) questionnaires, the ability of both phototherapies to reduce the provocation reaction and from the patients' evaluation of the long-term benefits of their phototherapies. RESULTS: Sixteen patients completed treatment with SunshowerMedical and thirteen completed treatment in hospital. Both types of phototherapy were effective. There was a highly significant improvement in DLQI with either treatment. In most cases, the hardening reduced or even completely suppressed clinical UV provocation of PLE. The patients using SunshowerMedical at home were, however, much more content with the treatment procedure than the patients visiting the dermatological units. CONCLUSIONS: Both treatments were equally effective in the induction of skin tolerance to sunlight in PLE patients. However, the home treatment was much better accepted than the treatment in the hospital.

Recalcitrant solar urticaria induced by UVA and visible light: a case report.

A 41-year-old man presented with a ten-year history of recurrent erythema and swelling of skin that occurred following sun exposure even as little as ten minutes. The lesion affected only on the sun exposed area. A phototesting was carried out and revealed that urticaria was induced following ultraviolet A (UVA) and visible light exposure. Solar urticaria (SU) from UVA and visible light was diagnosed. Many treatment options including combination of oral antihistamines, psoralen plus UVA (PUVA) photochemotherapy, narrowband UVB (NBUVB, 311 nm) phototherapy, and plasmapheresis were tried in the presented patient without significant response. Although various treatments are available, managing SU remains a challenging problem in many patients.

Clinical patterns of phytodermatitis.

Exposure to plants is very common, through leisure or professional activity. In addition, plant products and botanic extracts are increasingly present in the environment. Cutaneous adverse reactions to plants and their derivatives occur fairly frequently, and establishing the correct diagnosis is not always easy. The astute clinician relies on a detailed history and a careful skin examination to substantiate his opinion. This article reviews the characteristic clinical patterns of phyto- and phytophotodermatitis and some less common presentations.

Evaluation of photopatch test series in India.

Our aim was to evaluate the usefulness of TROLAB photopatch test series (supplemented with the plant extracts). 70 patients with dermatitis on photoexposed areas or dermatitis with photosensitivity were studied. Only 2 patients had photocontact allergy - 1 each to fragrance mix 8% and p-aminobenzoic acid 10%. Photocontact allergy to parthenium was seen in 4 and photoaggravation in 6 patients. Our results suggest that the TROLAB photopatch series are not useful for Indian patients with photodematoses.

[Eczematous skin diseases]. / Ekzemás megbetegedések.

The skin, as one of the most important barriers of the human body, protects the inner homeostasis from the harmful environmental influences as well as physical, chemical and biological factors. When the impact of these factors exceeds the tolerance and reproducing capacity of the skin, pathological alterations will develop. If follows from this that dermatology can surely be considered to be a part of environmental medicine. Eczematous diseases are mostly pathological pictures of varied mechanisms developing as a result of environmental influences (irritants, contact allergens, microbes). Since their clinical appearance is similar, it is a serious professional challenge to diagnose them. In this article we present the clinical features, provoking factors of these skin diseases as well as therapeutical possibilities.

Photocontact dermatitis.

Photocontact dermatitis is not a common condition, but neither is it rare. Both photo-irritant contact dermatitis (PICD) and photoallergic contact dermatitis (PACD) are seen by most dermatologists in general practice. PICD is diagnosed on clinical grounds and is usually caused by furocoumarins in plants like limes and celery. PACD is caused primarily by sunscreens but can also be the result of fragrances and antibacterial agents. PACD can only be diagnosed by photo-patch testing that most dermatologists, even those who patch test and give phototherapy in their office, do not perform. The procedure as outlined in this manuscript is relatively simple and can easily be accomplished in the dermatologist's office.

Clinical and therapeutic aspects of polymorphous light eruption.

BACKGROUND: Polymorphous light eruption (PLE) is an idiopathic eruption induced by ultraviolet (UV) radiation (UVR). OBJECTIVE: Evaluation of the clinical aspects, diagnostic criteria of PLE in a major Swiss referral center. METHODS: 25 patients with PLE were tested with a standardized protocol for the assessment of photodermatoses. RESULTS: 25 patients (22 women vs. 3 men) were identified. Papular and papular-vesicular eruptions were the most common clinical presentations. 6 of 25 patients had a reduced minimal erythema dose (MED) for UVA and 8 of 25 patients had a reduced MED for UVB. Photoprovocation was positive in 11 of 20 patients for UVA and 7 of 20 patients for UVB. Photohardening with narrow-band UVB was successful in 8 of 10 patients. Combined UVA/UVB therapy had a satisfactory effect in 10 of 15 patients. Narrow-band UVB therapy was still successful after ineffective UVA/UVB therapy. CONCLUSION: The MED was of no value for the diagnosis of PLE. The typical lesions were reproduced by UVA and UVB photoprovocation. We recommend photohardening with narrow-band UVB (311 nm).

Management of polymorphous light eruption : clinical course, pathogenesis, diagnosis and intervention.

Optimal management of patients with polymorphous light eruption (PLE), the most frequent photodermatosis, requires knowledge of the individual clinical course of the disease and pathogenic factors. As PLE often causes problems during leisure-time activities and holidays, resulting in a substantial loss of quality of life, prophylaxis is the most important therapeutic approach. Management of PLE must, therefore, focus on basic preventative measures and additional therapeutic approaches, depending on the clinical condition. PLE can be classified into four severity groups (mild, moderate-to-severe, severe and therapy-resistant), which are useful for determining appropriate prophylactic measurements. No specific laboratory tests are available for the diagnosis of PLE, therefore, a clinician must rely on the clinical appearance of the disorder (e.g. clinical symptoms, the location of the lesions, the relationship of the occurrence of the lesions with sun exposure and the time course of the lesions) as well as a patient's medical history in order to make a diagnosis. Basic preventative management of PLE consists of adequate sun protection comprising avoidance of sun exposure, the use of textile sun protection and the application of broadband sunscreens with high UVA protection potential. Other supportive measurements have to be managed individually and are dependent on the patient's medical history and the severity of the disease. Topical antioxidants, systemic immunomodulation, photo(chemo)therapy and systemic immunosuppression may be required in some cases of PLE. Topical antioxidants represent a new treatment approach for moderate-to-severe PLE and are an effective and well tolerated option for this patient population. Severe PLE also requires photo(chemo)therapy. Phototherapy can be in the form of 311 nm UVB or UVA1 irradiation. In cases where 311 nm UVB or UVA1 are ineffective, psoralen plus UVA (PUVA) bath therapy may be used. However, PUVA bath therapy must be used with caution because it is associated with acute and long-term adverse effects. In rare exceptions we would consider using oral PUVA therapy. However, in our outpatient department, quality of life of most patients is improved with the treatment regimens that are recommended for patients with moderate-to-severe PLE, without the need for photo(chemo)therapy.

Photocontact allergy to diallyl disulfide.

Although phototoxic reactions to plants are common, photoallergic contact dermatitis to plants and plant products rarely occurs. Our objective was to review the importance of including diallyl disulfide in the evaluation of patients with suspected photosensitivity. Phototests for ultraviolet B, ultraviolet A, and visible light as well as patch tests and photopatch tests for 49 allergens from the New York University Skin and Cancer Unit Photopatch Test Series were performed. Three patients had positive photopatch-test results to diallyl disulfide, which is the allergen in garlic. The authors conclude that although photocontact allergy to diallyl disulfide is rare, this allergen should be included in photopatch-test series.

[Plant-induced toxic and allergic dermatitis (phytodermatitis)]. / Durch Pflanzen ausgelöste toxische und allergische Dermatitis (Phytodermatitis).

Herbal products are being used increasingly for medical or cosmetic purposes. Many cosmetics contain plant extracts for fragrance. Sensitizing plants in cosmetics are tea tree oil, arnica, chamomile, yarrow, citrus extracts, common ivy, aloe, lavender, peppermint, and others. However, the sensitizing potential of these plants varies. Most of the sensitizing substances are sesquiterpene lactones or terpenes. The present paper reviews the various forms of phytodermatitis, including irritant plant dermatitis, phototoxic and photo-allergic dermatitis, allergic dermatitis, and airborne contact dermatitis.

The clinical and photobiological characteristics of solar urticaria in 40 patients.

Forty patients with solar urticaria, 16 male and 24 female, were examined personally during the past 25 years. The median age at onset of symptoms was 32 years, ranging from 13 to 76 years. Most commonly (45%) solar urticaria first appeared during the third decade. The mean duration of the disease was 3.6 years at presentation. The action spectrum was found in the visible light range in 24 patients (60%), in the ultraviolet (UV) A range in four, in the UVB in four, from the UVA to UVB in three, from the UVA to visible light in one and in a broad range from UVB to visible light in four patients. An inhibition spectrum was detected in 13 of 19 patients (68%), occurring at longer wavelengths than the action spectrum in 12 of these cases. The augmentation spectrum was found in only four of 14 patients (29%) examined. Twenty-four of 31 patients (77%) developed an urticarial reaction to autologous serum, which had been previously irradiated in vitro at the action spectrum for that patient. In a single patient, solar urticaria was caused by a drug, namely chlorpromazine. In two patients, polymorphic light eruption occurred in association with solar urticaria. No single modality of treatment was satisfactory, but combined use of antihistamines, sunbathing, psoralen UVA photochemotherapy and/or sunscreening agents partially suppressed the symptoms.

Clinical, laboratory, phototest and phototherapy findings in polymorphic light eruptions: a retrospective study of 133 patients.

In the present study, we retrospectively evaluated the clinical, laboratory, phototest and phototherapy findings in 133 patients (109 females and 24 males) with polymorphic light eruption (PLE). The median age of the patients at onset of PLE was 26 years (range, 3-62 years). The median duration of PLE at presentation was 6.5 years (range, 1 week to 25 years). Interestingly, we found two peaks in the distribution curve of the individual latent interval, the time between light exposure and the appearance of skin lesions. The first peak occurred at 1-1.5 hr and the second peak at 24 hrs after light exposure. Six of 33 patients tested had antinuclear antibodies (ANA). However, none of these ANA-positive patients had or developed systemic lupus erythematosus during follow-up. Phototesting revealed that minimal erythema doses for UVA and UVB fell within normal limits in 30 patients tested. Provocative phototesting was positive in 17 of 30 (57%) patients tested. The action spectrum fell within the UVA range in 10 (59%), the UVB range in 4 (23%), and both ranges in 3 (18%) of the 17 cases. Ninety-two patients received preventive phototherapy including broad-band UVB, broad-band UVA, or psoralen and ultraviolet A (PUVA). Follow-up information was available for 79 of these patients: the complete protection rate in the first summer season after therapy was 27% for UVB, 0% for UVA, and 53% for PUVA whereas the overall protection rate (including partial and complete responders) was 83% for UVA, 82% for UVB and 65% for PUVA. In contrast, the patients' histories revealed that the use of a sunscreen with a mean sun protection factor (SPF) of 14 did not prevent skin lesions in 88% of PLE patients.

Sesquiterpene lactone allergy.

Sesquiterpene lactones are a large, diverse group of chemicals found in several plant families that cause allergic contact dermatitis. The biological, botanical, allergenic, and structural significance of sesquiterpene lactones is explored as well as the clinical characteristics of cutaneous reactions. The association with UV-light sensitivity and proposed mechanisms for this relationship as well as new developments in patch test methods and treatment are reviewed.