Acute Erythema with Residual Hyperpigmentation

Abbas Charlie, MPH, and Naureen Shaikh, MD

A healthy 36-year-old male noticed intense painful red “sunburns” along the dorsum of his hands (Figure 1), especially the intertriginous webs of the fingers and the dorsum of his foot (Figure 2), while vacationing in Hawaii. He otherwise had no other skin lesions. His symptoms worsened within 24 hours, so he went to an urgent care clinic. 

Physical examination. The patient had nontender, well-defined, irregular bordered erythematous flat, nonpruritic lesions. He denied taking any medications or using new soaps, detergents, colognes, or lotions other than an SPF 60 sunscreen. 

The patient mentioned that he prepared ceviche, a popular Latin American dish consisting of seafood, lime, spices, and tomatoes, a day before the lesions appeared. 

Each lesion progressively darkened and became more sharply demarcated over the next 2 weeks and then slowly faded over the following 6 to 8 months. 

Discussion. Phytophotodermatitis is a phototoxic dermatologic reaction most commonly induced by contact with certain photosensitizing compounds containing furocoumarins (eg, lime, lemon, wild parsley, celery, and carrot) with subsequent exposure to ultraviolet light.1 It is therefore not an immunologic reaction, and no prior sensitizing exposure is necessary for this condition. 

Reactions are confined to the areas in contact with the photosensitizing agents and can produce erythema (with or without blistering) within 24 hours, while vesicles or bulla may develop within 72 hours after furocoumarin and sun exposure.2,3 Pruritus is usually not observed, however the lesions often cause a painful, tender, prickling, or burning sensation.4 Another hallmark of this condition is prominent hyperpigmentation, which appears 1 to 2 weeks after exposure that can persist for 6 to 12 months.2 Hyperpigmentation can appear as irregular streaks or well-demarcated patterns correlating to areas of contact of the photosensitizing agent.2

Phytophotodermatitis is self-limiting and treatment is mainly symptomatic.5 Painful lesions may respond to topical corticosteroids and cold compresses. It is also best to advise the patient to avoid contact of the photosensitizing agent and by protecting the skin from ultraviolet radiation.3,5,6

Differential diagnosis. A first-degree sunburn of the skin typically causes erythema that may be followed by epidermal desquamation, vesicles, plaques, and hyperpigmentation. This will affect all areas of skin exposed to the sun, which differentiates it from phytophotodermatitis. 

Allergic contact dermatitis is a delayed hypersensitivity reaction requiring prior sensitization to an allergen, which typically presents as pruritic vesicles or papules on an erythematous base.7 Patient also denied any use of “new soaps, detergents, colognes or lotions other than SPF 60 sunscreen.”

Porphyria cutanea tarda results from a deficiency of hepatic uroporphyrinogen decarboxylase that is commonly associated with oral contraception, excess alcohol consumption, estrogen use, and excess iron.8 Clinically, porphyria cutanea tarda typically presents with subepidermal bullae, hypertrichosis, and hyperpigmentation of sun-exposed areas.9

Patients stung by jellyfish usually experience immediate pain at the time of the envenomation and linear red urticarial lesions typically develop a few minutes later and not in a delayed fashion as described.10  


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