|Year : 1994 | Volume
| Issue : 3 | Page : 149-150
Minimal erythema dose to ultra-violet light in parthenium dermatitis
CR Srinivas, D Shrutakirthi Shenoi
C R Srinivas
Source of Support: None, Conflict of Interest: None
In Parthenium dermatitis, photosensitivity is a common feature. We studied the minimal erythema dose to UVA (2-18J/cm2) and UVB (30-70mj/cm2). MED to UVB was lowered in 9 cases but not detected in 1 whilst MED to UVA was seen in only 1 case. Reduction of MED to UVB is a definite indicator of photosensitivity in Parthenium dermatitis.
Keywords: Parthenium dermatitis, Minimal erythema dose
|How to cite this article:|
Srinivas C R, Shenoi D S. Minimal erythema dose to ultra-violet light in parthenium dermatitis. Indian J Dermatol Venereol Leprol 1994;60:149-50
|How to cite this URL:|
Srinivas C R, Shenoi D S. Minimal erythema dose to ultra-violet light in parthenium dermatitis. Indian J Dermatol Venereol Leprol [serial online] 1994 [cited 2019 Jul 17];60:149-50. Available from: http://www.ijdvl.com/text.asp?1994/60/3/149/4023
| Introduction|| |
Parthenium hysterophorus belongs to the family of compositae and is a common cause of air borne contact dermatitis (ABCD) with features suggestive of photosensitivity. Photocontact dermatitis secondary to Parthenium has been reported.  We undertook this study to determine the minimal erythema dose (MED) to UVB and UVA in ABCD to Parthenium.
| Materials and Methods|| |
10 cases of ABCD to Parthenium confirmed by patch testing were studied. MED to UVB (30 - 7OmJ/cm 2) and to UVA (2 - 18 J/cm 2) was determined using a whole body phototherapy unit obtained from Waldman. A template was used to deliver increasing doses of ultraviolet light over back . 
| Results|| |
[Table - 1] shows the MED values of the 10 cases, MED to UVB was significantly lowered in 9 (Mean: 33.3 mj/cm 2). MED to UVA was detected in only 1 case.
The minimal erythema dose (MED) is defined as the minimal single dose of ultraviolet radiation to produce a clearly marginated erythema at the irradiated skin site, expressed as energy per unit area, mj/ cm 2 or J/cm 2 for UVB and UVA respectively 3 reading being taken, after 24 hours for UVB and 48 hours for UVA.
| Comments|| |
History of inability to tolerate sunlight and heat is frequently elicited in Parthenium dermatitis. Photosensitivity is investigated by demonstration of MED and by photopatch testing. We found a significant loweing of MED to UVB (mean: 33.3 mj/cm 2), the MED for normal Indian skin beng 131 mj/cm 2 (personal observation). In Type III skin the MED may be as high as 300 mj/cm 2.  Photopatch testing with Parthenium in 3 of the present cases and in many of our earlier cases has been consistently negative with equal reaction in both irradiated and non-irradiated sites (unpublished observation), thus implying absence of photocontact allergy or phototoxicity. Compositae allergens do not apparently cause positive photopatch test reactions but have phototoxic properties in vitro. 
Reduction of MED to UVB is a definite indicator of photosensitivity in Parthenium dermatitis. MED to UVA should be attempted using a solar simulator or monochromator. The role played by infrared rays in the light exacerbation of Parthenium dermatitis needs further evaluation.
| References|| |
|1.||Bhutani L K, Rao D S. Photocontact dermatitis caused by Parthenium hysterophorus. Dermatologica 1978; 157: 206-9. |
|2.||Acharya S, Srinivas C R, Shenoy S D, et al. Determination of minimal erythema dose in Indian patients for ultraviolet- B phototherapy. Ind J Dermatol Venereol Leprol 1991; 57: 214-5. |
|3.||Norris P G, Gange R W, Hawk J L M. Acute effects of ultraviolet radiation on the skin. In : Dermatoloty in General Medicine, (Fitzpatrick TB, Eisen AZ, Wolff K, et al, eds) 4th edn. New York: Mc Graw - Hill, 1993; 1651. |
|4.||Wolff K, Gaschnait F, Honigamann H, et al. Phototesting and dosimetry for photochemotherapy. Br J Dermatol 1977; 96 : 1-10. |
|5.||Addo H A, et al. A study of Compositae plant extract reactions in photosensitivity dermatitis. Photodermatology 1985; 2 : 68. |
[Table - 1]
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