polymorphic light eruption
Last edited 08/2023 and last reviewed 08/2023
Polymorphic light eruption is a common idiopathic photosensitive disorder (1,2,3) which is frequently mis-diagnosed with miliara ("prickly heat") . It occurs in about 10-20% of the population with females affected more frequently than males in the ratio of 4:1 (3).
Presentation is usually in late adolescence and young adulthood, often early in the summer following exposure to ultraviolet (A and B wavelengths),intermittent eruption of non-scarring, erythematous itchy papules, plaques or vesicles induced by UV irradiation of sun-exposed skin (1,2)
- face, neck, and the upper and lower extremities are most commonly involved
- symptoms are worse in spring and early summer
- usually has its onset within the first three decades of life (3)
- also is a genetic component - appears to cluster in families: it has been estimated that the prevalence of PLE was 21 and 18% in monozygotic and dizygotic twins, respectively (2)
Click here for images of polymorphic light eruption
First line of treatment for polymorphic light eruption includes sun avoidance, sunscreens and topical corticosteroids (2)
- new generation broad-spectrum sunscreens, with high sun protection factor for UVB (SPF), together with longer wavelength UVA protection, have been reported to confer total or partial protection in up to 90% of patients
- second line therapies includes systemic corticosteroids and photo(chemo)therapy (2)
Prognosis
- study evidence revealed disease improved in a substantial number of patients (i.e., 77% of females and 59% of males) over the years, it took 25 years until one third of patients had normalized from polymorphic light eruption (3)
- persistence of skin lesions for more than 1 week under daily life conditions may predict a prolonged course of the disease over the years
Notes:
- polymorphic light eruption in Indian skin
- unique feature of this condition in Indian skin is the pigmentary change which varies from hypopigmented to hyperpigmented lesions (4)
- pigmentary changes may occur alone or in combination with erythematous or skin-colored lesions
- pigmentary lesions are seen in more than 50% of lesions
- pigmentary changes may persist after the lesions subside
- unique feature of this condition in Indian skin is the pigmentary change which varies from hypopigmented to hyperpigmented lesions (4)
Reference:
- (1) Morison WL. Photosensitivity. N Engl J Med. 2004;350(11):1111-7.
- (2) Lembo S, Raimondo A. Polymorphic Light Eruption: What's New in Pathogenesis and Management. Front Med (Lausanne). 2018 Sep 10;5:252. doi: 10.3389/fmed.2018.00252.
- (3) Gruber-Wackernagel A, Schug T, Graier T, Legat FJ, Rinner H, Hofer A, Quehenberger F, Wolf P. Long-Term Course of Polymorphic Light Eruption: A Registry Analysis. Front Med (Lausanne). 2021 Jul 16;8:694281. doi: 10.3389/fmed.2021
- (4) Karthikeyan K, Aishwarya M. Polymorphous Light Eruption- An Indian Scenario. Indian Dermatol Online J. 2021 Mar 2;12(2):211-219.