Photoallergic contact dermatitis

Abstract

Many topical photoallergic culprits have been reported in the literature, the most important of which are sunscreen agents and, recently, non-steroidal anti-inflammatory agents (NSAIDs). Not at all exceptional is the occurrence of photoaggravation and recurrent transient or even persistent light reactions on previously exposed as well as non-exposed areas (often sparing the original application site), particularly with the NSAID ketoprofen. Moreover, cross-reactions with chemically-related as well as non-chemically related molecules are common. The potentially misleading clinical features observed in some cases, the diversity of the casual substances identified, and the low frequency with which photopatch testing is carried out in general indicate that the occurrence of photoallergic contact dermatitis might well be underestimated.

Sunscreens: An overview and update

“…56 True allergic contact dermatitis is rarely caused by sunscreen ingredients, 57 although its incidence may be underestimated. 58 PABA and oxybenzone are the most common contact photoallergens in use today, whereas avobenzone, sulisobenzone, octinoxate, and padimate O have fewer reported reactions. 57 Patients with photodermatoses and eczema may be predisposed to developing photoallergy and should be counseled appropriately.…”

Photo Allergic Contact Dermatitis: The 15-Year Experience of a Tertiary Reference Center in a Sunny Mediterranean City

“…It may be acute, subacute, or chronic, and shares common features with phototoxic reactions. The photoallergen may be transferred from one body site to another, for example, to the contralateral areas, and may be due to a cross-leg effect or to transfer by the hands; furthermore, the original application site may not be affected (2).…”

Photoallergy

“…Involvement of these shaded areas suggests dermatitis from an airborne allergen or irritant, although in severe and/or chronic cases, these areas may also become involved (32,53). An airborne allergen may also be a photosensitizer, examples of such cases are airborne PACD from crushed chlorpromazine tablets and occupational exposure to olaquindox (a veterinary antibiotic, no longer used in Europe) (5,9,54,55).…”

“…Higher index of clinical suspicion correlates with higher likelihood of positive reaction to photopatch test. Despite lack of documented epidemiologic data, photoirritation is considered more common than photoallergy (29,32).…”