Solar Urticaria a Report of 25 Cases and Difficulties in Phototesting

OBSERVATION Solar Urticaria A Report of 25 Cases and Difficulties in Phototesting

Stephanie Ryckaert, MD; Rik Roelandts, MD, PhD

Background: Solar urticaria is a rare photosensitive dis- Conclusions: A negative phototest result from a single ease, and its differential diagnosis with respect to poly- light source does not necessarily exclude a diagnosis morphous light eruption is sometimes difficult. We re- of solar urticaria. In patients in whom phototesting elic- port our experience with 25 cases of solar urticaria and its negative reactions, other light sources should be discuss the pitfalls in phototesting such patients. used, and, if the phototest result is still negative, a provocative test with natural sunlight should be done. Observation: The most important locations in this pa- Histamine1-receptor antihistamines are a useful first- tient series are the V of the neck and the arms, which are line therapy, although more severely affected persons similar to those of polymorphous light eruption. In all may require prophylactic courses of phototherapy or of the patients, however, the lesions appeared within 30 photochemotherapy. The main problem is maintenance minutes of sun exposure or phototesting and disap- treatment. peared within 24 hours. Notably, 12 (48%) of the patients had a history of atopy. Phototesting helps con- firm the diagnosis, but, in some patients, this was difficult. Arch Dermatol. 1998;134:71-74

OLAR URTICARIA can be de- 14 of them had both erythematous lesions fined as an idiopathic photo- and whealing. In all of the 25 patients, ery- dermatosis characterized by thema or urticaria and itching appeared 30 the occurrence of itchy ery- minutes or less after sun exposure. The time thematous or urticarial le- the urticaria persisted varied from 30 min- sionsS that are provoked only by sunlight and utes or less (n=7) to 1 to 2 hours (n=6) to disappear rapidly, nearly always within 24 several hours (n=12). When the sun expo- hours after the avoidance of sun exposure was avoided, the lesions always disap- sure. The severity of the reaction depends peared within 24 hours, which is the most on the length of time of the exposure and important clinical diagnostic criterion. the intensity of the solar irradiation. The location of solar urticaria can We describe the difficulties in diag- vary. In our series, 24 patients had le- nosing solar urticaria in a series of 25 pa- sions on the V area of the neck; 24 on the tients. The clinical features needed for the arms; 24 on the legs; 20 on the shoul- diagnosis of solar urticaria are evaluated, and ders; 19 each on the trunk, the neck, the we discuss the necessary confirmation by hands, and the feet; 18 on the ears; 15 on phototesting. Indeed, the reproducibility of the cheeks; 14 on the forehead; 9 on the the lesions as a diagnostic element is not al- nose; and 5 on the eyelids. Thus, the most ways easy. Finally, we analyze the differ- frequent locations are the V area of the ent treatment modalities. neck and the arms, which is similar to those of polymorphous light eruption. RESULTS Therefore, the location of the lesions is less important in confirming the CLINICAL FINDINGS diagnosis than is their short persistence. Only in 7 (28%) of our patients was In this series of 25 patients with solar ur- there spontaneous improvement in the sum- ticaria, the age at first consultation varied mer, which means that most of them did not between 17 and 71 years, with a mean age develop a natural tolerance during the sum- of 35 years. The solar urticaria had started mer. One reason for this could be that most from 4 to 11 years before consultation. of them did not expose their skin regularly All the patients had itching; 9 of the 25 enough to the sun out of fear of a relapse, but also had a burning sensation, and 1 even had another reason could simply be the climate From the Photodermatology pain. Five patients had only itchy erythem- in Belgium. That most of the reported cases Unit, University Hospital, atous lesions, whereas in 20 patients wheal- occur in northern countries could be due to Leuven, Belgium. ing developed with exposure to the sun, and a continuous desensitization in southern

ARCH DERMATOL / VOL 134, JAN 1998 71

©1998 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 09/23/2021 radiation. The other reacted also to irradiation with a PUVA irradiation box. The third patient did not react at all and PATIENTS AND METHODS was further tested with a solar simulator, but again with negative results. Only a provocative test with sun expo- PATIENTS sure elicited a positive reaction in this patient (Table 2).

The 25 patients with solar urticaria were diagnosed on the basis of an exhaustive list of questions about COMMENT the aspect of the lesions, the location, the relationship with sun exposure and sun intensity, the dura- The diagnosis of solar urticaria on clinical grounds is dif- tion of sun exposure needed, the time during which ficult because the lesions persist for such a short time, and lesions persist after the avoidance of exposure, the most patients who consult a physician for this have no le- evolution during the summer, the personal and fa- sions at all. The diagnosis cannot be made with certainty milial medical history, and the use of sunscreen oint- merely on the basis of the history. Therefore, it has to be con- ments or other preventive measures. firmed by phototesting, which is also necessary to determine the degree of photosensitivity and the action spectrum. PHOTOTESTING The immediate initial reading is the most important one for this condition. It is also advisable to read the tests after Several lamps can be used for phototesting. Fluores- cent tubes are inexpensive and available with several 6 hours because late reactions are possible, albeit rare. At a emission spectra. A more expensive but also more particular wavelength, the threshold dose (MUD) is the dose physiologic technique is to use a solar simulator (a xe- in millijoules or joules per square centimeter that induces non lamp). The most detailed phototesting proce- a clearly visible itchy erythema or whealing during or shortly dure is to use a xenon lamp in combination with a after irradiation. This reaction mostly disappears in a few monochromator to determine the minimum urti- minutes but may last for several hours. If the dose is below carial dose (MUD) at different wavelengths. The 25 the MUD, there is no reaction or only slight immediate ery- patients were tested in this way with a Clinical Photo- thema without itching confined to the irradiated site. With irradiator UV 90 (Applied Photophysics, London, En- doses at or slightly higher than the MUD, erythema precedes gland), which combines a 900-W xenon lamp with a whealing. When the threshold dose is exceeded a great deal, monochromator. The following wavelengths were used: 300, 320, 350, 400, 500, and 600 nm. Those patients whealing develops without the preceding erythema. In 2 of who reacted to 600 nm were also tested at 700 nm. the3patientsinwhommonochromatictestresultswerenega- tive, a positive reaction with itchy erythema and whealing was provoked with the use of the slide projector. Although the phototest results with a slide projector, a high-intensity countries. Indeed, in our series, there did not appear to be UV-A source, a PUVA irradiation box, and total-spectrum any relationship between the occurrence of solar urticaria xenon light remained negative in the third patient, a pro- and the white skin type. vocative test with sun exposure elicited a positive reaction Of the 25 patients, 16 (64%) had a history of regu- (Table 2). From a practical point of view, when monochro- lar herpes infection and 12 (48%) had atopy, with a his- matic phototest results are negative, it is important to con- tory of asthma, hay fever, or atopic dermatitis. Of the 13 tinue provocative testing with other light sources. Only then who were not themselves atopic, 4 (31%) had atopy in may a diagnosis of solar urticaria be excluded. With the sim- the immediate family. Of the 25 patients, 7 (28%) (wom- pler tests, the precise action spectrum cannot be determined en) were using hormonal therapy. but only the diagnosis confirmed. Some patients require not only UV or visible irradiation or both to reproduce the ur- PHOTOTESTING ticarial wheals but also heat.1 Knowing the precise action spectrum can be important because it enables the physician With monochromatic phototesting, it was possible to de- to make a qualitative and quantitative evaluation of the pho- termine the action spectrum and the degree of photosen- tosensitivity, evaluate the effect of treatment, and observe sitivity in 22 of our patients (88%) (Table 1): 6 (27%) the evolution of the condition over time. In addition, it can reacted to 300 nm, 10 (45%) to 320 nm, 15 (68%) to 350 be useful in formulating guidelines for a patient. nm, 14 (64%) to 400 nm, 10 (45%) to 500 nm, and 2 (9%) Themostdifficultdifferentialdiagnosisispolymorphous to 600 nm. In 3 patients (patients 23, 24, and 25), the re- light eruption. The most frequent locations of solar urticaria sults of the monochromatic testing were normal (Table 2). are the V area of the neck and the arms, which is similar to Because the patient history was suggestive for solar urti- those of polymorphous light eruptions, although more pa- caria, additional phototesting was done with a slide pro- tients with solar urticaria also have facial lesions than do pa- jector (Carousel S-AV 1010, Kodak, Stuttgart, Germany), tients with polymorphous light eruptions. Unlike solar ur- a high-intensity UV-A source (UVASUN 3000, Mutzhas, ticaria, the lag time for the appearance of polymorphous light Munich, Germany), a psoralen plus UV-A (PUVA) irra- eruption varies between 2 hours and 3 days after sun expo- diation box with Philips Cleo lamps (Alfasun, BLS, Wolver- sure,and,intheabsenceoffurtherexposure,itgenerallytakes tem, Belgium), a total-spectrum xenon light without UV-C 2 to 6 days or even longer before the lesions disappear. So- (Clinical Photo-irradiator UV 90), or sun exposure. With lar urticaria also has to be differentiated from erythropoi- the slide projector, a positive reaction with itchy ery- etic protoporphyria,2 in which sun-induced urticaria can be thema and whealing was provoked in 2 of the 3 patients. one of the symptoms. Erythropoietic protoporphyria usu- One of these reacted to the UV-A high-intensity source ir- ally starts in infancy, is often familial, and has skin pain as

ARCH DERMATOL / VOL 134, JAN 1998 72

©1998 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 09/23/2021 Table 1. Values of the Minimal Urticarial Dose in Joules per Square Centimeter at Different Wavelengths in 25 Patients With Solar Urticaria as Determined With a Xenon Lamp and a Monochromator After Immediate Reading*

Wavelengths, nm† Patient No. 300±5 320±10 350±32 400±32 500±32 600±32 700±32 1− − −Յ25 Յ35 − ND 2− − 20Յ25 Յ35 − ND 3− − 40− − NDND 4−4 28− − NDND 5 0.056 1.40 −−−−ND 6 − − 40 100 − ND ND 7 0.040 0.25 2.0 − ND ND ND 8 − 0.25 Յ0.3 19 − ND ND 9 0.028 0.10 Յ0.1 Յ25 Յ35 Յ50 − 10 0.056 0.50 20 − − ND ND 11 0.056 0.17 1.2 50 − ND ND 12 − − 3.5 5 5 3 − 13 − − 14 100 Յ35 − ND 14 − 2.80 −−−−− 15−−−−Յ35 − ND 16 − − − Յ25 Յ35 − ND 17 − 0.08 Յ0.1 Յ25 Յ35 − ND 18 − − − Յ25 22 − ND 19 − − − Յ25 Յ35 − ND 20 0.056 0.10 1 50 − − ND 21 − − 28 − − − ND 22 − − 28 Յ25 − ND ND 23−−−−−NDND 24−−−−−−ND 25−−−−−−ND

*The minus sign means that the phototest results at this wavelength are negative; ND, not done. †The plus or minus sign signifies the band width in nanometers of the monochromator at this wavelength.

Table 2. Induction of Whealing in Patients With Solar Urticaria Using Different Light Sources*

Light Source

Patient Monochromatic Phototesting, Slide UVASUN PUVA Irradiation Total-Spectrum No. 300 to 600 nm† Projector 3000 Box Xenon Light Sunlight 23 − + + ND ND ND 24 − + ND + ND ND 25 − − − − − +

*See the text for the descriptions and manufacturers of the different light sources. A minus sign indicates no wheal; a plus sign, whealing. †See Table 1 (details are given for 300, 320, 350, 400, 500, and 600 nm for these 3 patients). the predominant symptom. In addition, porphyrin dosages will induce immediate reactions in patients with solar ur- will show elevated protoporphyrin levels in the blood; in so- ticaria and may induce delayed reactions in patients with lar urticaria, these levels are normal by definition. There- lupus erythematosus. Finally, test results for anti- fore, porphyrin determinations are only necessary when the nuclear and Ro skin-sensitizing antibodies (Ro SSA) will solar urticaria starts in infancy, when skin pain is the pre- be negative in patients with solar urticaria. dominant symptom, or when both are present. Once urticaria has developed, the treatment is only The experimental induction of immediate whealing symptomatic. Topical or oral antihistamines can be used, has also been reported in a case of porphyria cutanea tarda,3 as can topical steroids. The urticarial response can also be but, again, the porphyrin dosages were abnormal. decreased by cooling the corresponding areas of the skin Cholinergic urticaria may occasionally mimic solar ur- immediately after irradiation.4 It is more important to try ticaria in that it can be precipitated by the heat occurring to prevent whealing. The choice of the treatment and the during sun exposure. Solar urticaria, however, will be more response to the treatment will then depend mainly on 2 pronounced on the exposed skin areas, whereas choliner- factors: the action spectrum to which the patient reacts gic urticaria is usually more pronounced in the covered ar- and the severity of the lesions as expressed by the MUD. eas, where the temperature is higher. In patients with cho- The usefulness of topical broadband sunscreens is linergic urticaria, phototesting will elicit negative reactions. limited to those patients with a narrow action spectrum The cutaneous lesions in lupus erythematosus may in either or both the UV-B and the shorter UV-A range show a photodistribution, but they will not be urti- (320-360 nm) and where the MUD is not too low. Be- carial. Moreover, lupus lesions will persist for at least sev- cause many patients are also sensitive to longer wave- eral weeks, whereas solar urticaria will nearly always dis- lengths, sunscreens, even those providing broad protec- appear within 24 hours after sun avoidance. Phototesting tion, will seldom give satisfactory improvement.

ARCH DERMATOL / VOL 134, JAN 1998 73

©1998 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 09/23/2021 Antimalarial agents,5 oral ␤-carotene,6,7 and oral ste- Another successful but more invasive and, there- roids4 are of little value in the treatment of solar urticaria. fore, less practical therapy is plasmapheresis. It can be Antihistamines are still the therapy of first choice be- used in those patients in whom a photoallergen can be cause histamine may be an important mediator in solar found in plasma or serum.28-33 This treatment can also urticaria. Antihistamines can reduce the whealing and itch- be combined with PUVA.34 ing in many patients.4,8 Especially interesting are the antihistamines of the new generation, among which the Accepted for publication July 22, 1997. 9 H1-receptor antihistamines are generally superior. Many Reprints: Rik Roelandts, MD, Photodermatology Unit, studies conducted to date have been done with terfen- University Hospital, Kapucijnenvoer 33, B-3000 Leuven, adine.10-16 To obtain good therapeutic results, much higher Belgium. doses than the conventional dosage are needed (180-360 10,14,15 mg/d), with which success rates as high as 77% have REFERENCES been reported.15 Edema and itching can thus be prevented, althoughmacularerythemacanstillbepresent.Afterawhile, 1. Shelley WB, Heaton CL. Pathogenesis of solar urticaria: sweat droplet in testing the dose can be decreased. In many cases, 120 mg/d is for photosensitivity. Arch Dermatol. 1976;112:850-852. 2. Beljaards RC, Bruynzeel DP. Solar urticaria and disturbed metabolism of por- sufficient as maintenance treatment. A higher dosage of phyrins. Dermatologica. 1991;182:231-232. terfenadine than the conventional dosage can cause adverse 3. Ichihashi M, Hasel K, Horikawa T. A case of porphyria cutanea tarda with experimental light urticaria. Br J Dermatol. 1985;113:745-750. effects and lead to rare but life-threatening cardiac dysrhyth- 4. Illig L. Untersuchungen zur Pathogenese der Lichturticaria, I: Mitteilung. Arch 17 mias. The question is how this medication achieves its Klin Exp Derm. 1963;217:82-116. effect because effective doses are much higher than would 5. Lorincz AL. Solar urticaria. Ill Med J. June 1964:626-628. 6. Kobza A, Ramsay CA, Magnus IA. Oral ␤-carotene therapy in actinic reticuloid be needed to only block the histamine liberator. Some pa- and solar urticaria. Br J Dermatol. 1973;88:157-166. tients have clinical improvement with terfenadine therapy 7. Neittaanma¨kiH,Jaä¨skelaïnen T, Harvima RJ, Fra¨ki JE. Solar urticaria. Photoder- but with little modification of the phototest results.18 matology. 1989;6:52-55. 8. Baart de la Faille H, Rottier PB, Baart de la Faille-Kuyper EH. Solar urticaria: a In patients in whom antihistamines do not give a sat- case with possible increase of skin mast cells. Br J Dermatol. 1975;92:101-107. isfactory result, phototherapy and photochemotherapy are 9. Diffey BL, Farr PM. Treatment of solar urticaria with terfenadine. Photoderma- tology. 1988;5:25-29. worth trying. Even if detailed phototesting was done be- 10. Rajatanavin N, Bernhard JD. Solar urticaria. J Am Acad Dermatol. 1987;18:574. fore, it is advisable to determine the MUD again with the 11. Mitchell P, Hawk J, Shafrir A, Corbett MF, Magnus IA. Assessing the treatment lamps and, if possible, with the light box used for the thera- of solar urticaria. Dermatologica. 1980;160:198-207. 12. Ferguson J. Idiopathic solar urticaria: natural history and response to non- peutic irradiations. The main reason for this is to avoid a sedative antihistamine therapy. Br J Dermatol. 1988;119(suppl 33):16. generalized flare-up. Phototherapy has the advantage over 13. Bilsland D, Ferguson J. A comparison of cetirizine and terfenadine in the manage- photochemotherapy of not provoking phototoxic adverse ment of solar urticaria. Photodermatol Photoimmunol Photomed. 1991;8:62-64. 14. Royer P, Pompougnac E, Beylot C. Traitement de l’urticaire solaire par la ter- effects and probably of not having the same adverse ef- feńadine: a propos d’un cas. Nouv Dermatol. 1992;11:311-312. fects over the long term. It can be done with repeated ex- 15. Manciet J, Jeanmougin M, Freychet F, Dubertret L. Traitement de l’urticaire solaire: 19 20,21 a propos de 18 cas: place de la terfeńadine. Nouv Dermatol. 1992;11:312-316. posures to narrowband UV-B, broadband UV-B, UV-A 16. Tsien A, Schanker H. Solar urticaria: a case report. Cutis. 1996;57:87-90. 22,23 24 alone, or a combination of UV-B and UV-A. Photo- 17. Bernhard JD. Treatment of solar urticaria with terfenadine. J Am Acad Dermatol. therapy can also be done with visible light. It has been shown 1993;28:668. 18. Alcaraz I, Bonnevalle A, Boudiquet JP, Rousseaux I, Thomas P. Alarming pho- that daily irradiations with fluorescent lamps emitting tobiological investigations, an unexpected tolerance acquired: the case of a so- mainly blue light can provide good protection.25 The tol- lar urticaria. Nouv Dermatol. 1994;13:379-382. erance obtained with phototherapy decreases quickly and 19. Collins P, Ferguson J. Narrow-band UVB (TL-01) phototherapy: an effective pre- 26 ventative treatment for the photodermatoses. Br J Dermatol. 1995;132:956-963. is mostly gone in a few days. Better results are obtained 20. Machet L, Vaillant L, Muller C, Henin P, Brive D, Lorette G. Traitement par UVB with PUVA therapy, especially in those patients for whom the´rapie d’une urticaire solaire induite par les UVA. Ann Dermatol Venereol. 1991; 118:535-537. all other therapy was unsuccessful. In contrast with the tol- 21. Kalimo K, Jansen C. Severe solar urticaria. Photodermatology. 1986;3:194-195. erance induced by sun exposure or by UV phototherapy, 22. Juhlin L, Malmros-Enander I. Solar urticaria. Photodermatology. 1986;3:164- the protection obtained with PUVA lasts many weeks. 168. 23. Bernhard JD, Jaenicke K, Momtaz TK, Parrish JA. Ultraviolet A phototherapy in Usually the UV-A irradiations are given 2 hours af- the prophylaxis of solar urticaria. J Am Acad Dermatol. 1984;10:29-33. ter oral intake of 0.6 mg/kg of 8-methoxypsoralen 3 times 24. Wolska H, Kleniewska D, Kowalski J. Successful desensitization in case of solar a week. We start the regimen at a dose under the MUD urticaria with sensitivity to UVA and positive passive transfer test. Dermatosen. 1982;30:84-86. and increase it by 20% twice a week. In those patients in 25. Diffey BL, Farr PM, Ive FA. Home phototherapy of solar urticaria. Photoderma- whom the MUD is so low that PUVA treatment would tology. 1984;1:145-146. 26. Ramsay CA. Solar urticaria treatment by inducing tolerance to artificial radiation be nearly impossible, pre-PUVA UV-A desensitization can and natural light. Arch Dermatol. 1977;113:1222-1225. 27 be done. Before starting PUVA treatment, the patient 27. Roelandts R. Pre-PUVA UVA desensitization for solar urticaria. Photodermatol- is irradiated with UV-A without psoralens for 3 days with ogy. 1985;2:174-176. 28. Leenatuphong V, von Kries R, Ho¨lze E, Plewig G. Solar urticaria induced by vis- 6 irradiations, increasing the dosages every day hourly. ible light and inhibited by UVA. Photodermatology. 1988;5:170-174. In this way, the MUD will gradually increase. As soon as 29. Leyen P, Duschet P, Schwarz T, Ho¨cker P, Gschnait F. Plasmapheresis in urti- the MUD is at least 1.5 J/cm2 of UV-A, the classic PUVA caria solaris. J Invest Dermatol. 1986;86:323-324. 30. Duschet P, Leyen P, Schwarz T, Ho¨cker P, Greiter J, Gschnait F. Solar urticaria— treatment with psoralens can be started. Repeating the effective treatment by plasmapheresis. Clin Exp Dermatol. 1987;12:185-188. phototesting after 10 sessions, we have obtained spec- 31. Leenutaphong V, Ho¨lzle E, Plewig G, Grabensee B, Kutkuhn B. Plasmapheresis in solar urticaria. Photodermatology. 1987;4:308-309. tacular increases in the MUD by a factor of as high as 200. 32. Duschet P, Schwarz T, Gschnait F. Plasmapherese bei Lichturtikaria. Hautarzt. Nevertheless, the MUD value returns to the initial level 1989;40:553-555. within 3 months. With this in mind, we are considering 33. Leenutaphong V, Ho¨lzle E, Plewig G, Kutkuhn B, Grabensee B. Plasmapheresis in solar urticaria. Dermatologica. 1991;182:35-38. maintenance therapy with UV-A only, for example, once 34. Hudson-Peacock MJ, Farr PM, Diffey BL, Goodship THJ. Combined treatment of or twice a week. The literature is silent on this subject. solar urticaria with plasmapheresis and PUVA. Br J Dermatol. 1993;128:440-442.

ARCH DERMATOL / VOL 134, JAN 1998 74