The correct answer is Poikiloderma of Civatte (POC; choice “a”), a consequence of extensive and poorly tolerated sun exposure. Although it is the result of multiple sunburns, POC is permanently fixed to affected skin, not merely a temporary phenomenon like sunburn—so choice “b” is incorrect.
Some forms of lupus (choice “c”) present with redness, but it tends to be of acute onset (in the beginning at least) and will usually involve epidermal disturbance (eg, scaling or erosions). The condition often manifests as discrete and confluent lesions with clearing centers.
Rosacea (choice “d”) can affect the neck and face. However, it will typically wax and wane, and will often involve papules and pustules as well. By contrast, POC is basically unchanging and has no palpable component.
POC is one of many indices of dermatoheliosis (chronic sun damage) and is reportedly more common in women, although it is not at all unusual in men with a history of overexposure to ultraviolet light sources. As this case demonstrates, POC often develops so gradually that even patients with pronounced involvement of several years’ duration may not be aware of their condition until it is pointed out to them.
The history of overexposure to the sun, the photodistribution of the erythema, and the distinct sparing provided by the chin all serve to confirm the nature of the problem. So too does the presence of multiple other indices of dermatoheliosis, such as actinic keratoses, solar lentigines, weathering, and the stellate scars on the dorsal arms of older patients.
Affected patients need a thorough skin check for possible malignancies at the time of the initial visit, with arrangements made for ongoing periodic checks. Patient education on the need for better sun protection can be reinforced by providing samples of sunscreen products. The diagnosis of POC is often a shock to patients, but the occasion provides the perfect opportunity to educate them about the effects of chronic overexposure to the sun.
For pronounced cases such as this one, ablation with the appropriate laser is, by far, the most effective option. But since POC is not truly a disease, most patients are content to learn the nature of their diagnosis and their role in limiting its worsening.