Photoaggravated skin disorders are diseases that occur without UV radiation but are sometimes or frequently exacerbated by UV radiation. In conditions, such as lupus erythematosus, photoaggravation occurs in a majority of patients, whereas in conditions, such as psoriasis and atopic dermatitis, only a subset of patients demonstrate photoaggravation. Polymorphous light eruption is a common photodermatosis in all skin types, making it important to differentiate photoaggravation of an underlying disorder, such as lupus erythematosus, from superimposed polymorphous light eruption. Disease-specific treatments should be instituted where possible. A key component of management of photoaggravated conditions is photoprotection with behavioral change, UV-protective clothing, and broad-spectrum sunscreen.
Key points
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Photoaggravated skin disorders are diseases that occur as entities without UV radiation (UVR).
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They can be subdivided into conditions that are frequently exacerbated by UVR and conditions that are sometimes exacerbated by UVR.
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Conditions frequently exacerbated by UVR include cutaneous lupus erythematosus (LE), Darier disease (DD), dermatomyositis (DM), lichen planus (LP) actinicus, pellagra, rosacea, and Smith-Lemli-Opitz syndrome.
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Conditions sometimes exacerabated by UVR include acne, atopic dermatitis (AD), carcinoid syndrome, cutaneous T-cell lymphoma, erythema multiforme, pemphigus, pityriasis rubra pilaris, psoriasis, reticulate erythematous mucinosis syndrome, seborrheic dermatitis, transient acantholytic dermatosis (Grover disease), and viral infections.
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Polymorphous light eruption (PMLE) is a common photodermatosis, making it important to differentiate photoaggravation of an underlying disorder from superimposed PMLE.
Introduction
Photoaggravated skin disorders are diseases that occur as entities without UV radiation (UVR) but are sometimes or frequently exacerbated by UVR. The specific UV wavelengths most capable of causing a flare in the disease are referred to as the action spectrum, and many photoaggravated diseases have distinct action spectra. In conditions, such as lupus erythematosus (LE), photoaggravation occurs in a majority of patients, and photoprotection is an essential component of management. In conditions, such as psoriasis and atopic dermatitis (AD), exposure to UVR results in improvement in a majority of patients but may exacerbate a subset. Photoaggravated conditions affect both fair-skinned and dark-skinned individuals. A recent study from India of 362 patients with Fitzpatrick types IV or V skin who were suspected of having a photodermatosis documented a range of photoaggravated conditions: AD in 6.1%, systemic LE (SLE) in 3.6%, discoid LE (DLE) in 3%, rosacea in 3.3% (topical steroid–related in 2.2%), actinic lichen planus (LP) in 2.2%, dermatomyositis (DM) in 1.2%, and photoaggravated psoriasis in 0.6%.
PMLE is a common photodermatosis in all skin types; therefore, it is important to differentiate photoaggravation of an underlying disorder from superimposed PMLE. Among patients with suspected PMLE, up to 10% are subsequently diagnosed with LE, making this an important differential. True photoaggravation causes exacerbation of the primary disease-specific lesions, and histology reflects the underlying dermatosis.
Disease-specific treatments should be instituted where possible. A key component of management of these photoaggravated conditions is photoprotection in the form of sun avoidance between 10:00 am and 4:00 pm in temperate zones and use of long-sleeved clothing, wide-brimmed hats, and broad-spectrum sunscreen. When photoprotection is advised, consideration should be given to vitamin D supplementation.
Counterintuitively, in photoaggravated conditions, if photoprotection and disease-specific measures prove insufficient, low-dose phototherapy may be indicated. The study of this group of disorders is hampered by inconsistent terminology; for example, the terms, photosensitive psoriasis, photoaggravated psoriasis , and photoexacerbated psoriasis , describe the same subset of patients.
This article covers the conditions usually exacerbated by UVR and briefly covers a selection of conditions sometimes exacerbated by UVR ( Box 1 ).
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