Confetti-like Sparing: A Diagnostic Clinical Feature of Melasma

Abstract

Diagnostic uncertainty when a patient presents with melasma-like Undings can lead to suboptimal treatment and inaccurate prognostic expectations. In this study, the authors present a unique clinical feature of melasma that they term the "Fitzpatrick macule" and test its Utility in establishing diagnostic certainty. The "Fitzpatrick macule" is a confetti-like macule of regularly pigmented skin located within a larger patch of melasma hyperpigmentation. To test its diagnostic Utility, the authors compared clinical photography of known cases of melasma with common mimickers, such as poikiloderma of Civatte and solar lentiginosis, and determined the positivity rate of the Fitzpatrick macule in each scenario. Their results show that 89.1 percent of clinical photographs of melasma were positive for the presence of Fitzpatrick macules compared to 1.1 percent that were negative. In contrast, 37.5 and 56.3 percent of clinical photographs of poikiloderma of Civatte were positive and negative for Fitzpatrick macules, respectively. Solar lentiginosis showed a 5.6 percent positivity and a 77.8 percent negativity for Fitzpatrick macules. The sensitivity and specificity of Fitzpatrick macules for melasma was 99 and 83 percent, respectively. In summary, the authors report a highly sensitive and specific clinical feature of melasma. In cases of diagnostic uncertainty, the presence of Fitzpatrick macules may aid in establishing a diagnosis of melasma.

Figure 1.

The Fitzpatrick macule. A) Note the macular islands of sparing within hyperpigmented patches of melasma. B) Subtle Fitzpatrick macules noted to the left lateral forehead. C) A case of actinic dyschromia with mottled dyspigmentation. It can be distinguished from melasma by the absence of Fitzpatrick macules.

Figure 2.

Melasma hypervascularity. Using VISIA Complexion Analysis, two random patients with melasma in the authors’ practice were analyzed for pigmentary and hypervascular changes (A and B). Note the association of hypervascularity with hyperpigmentation. Interestingly, the Fitzpatrick macule is relatively spared of hypervascularity (arrows).

Figure 3.

Prevalence of Fitzpatrick macules in patients with known facial melasma. 89.1% (n=82) were positive, 1.1% (n=1) were negative, and 9.8% (n=9) were indeterminate for Fitzpatrick macules. p<0.0001.

Figure 4.

Prevalence of Fitzpatrick macules in patients with poikiloderma of Civatte. 37.5% (n=6) were positive, 56.3% (n=9) were negative, and 6.2% (n=1) were indeterminate. No statistically significant difference could be detected between positive and negative groups.

Figure 5.

Prevalence of Fitzpatrick macules in patients with solar lentiginosis. 5.6% (n=1) were positive, 77.8% (n=14) were negative, and 16.7% (n=3) were indeterminate for the presence of Fitzpatrick macules. p<0.0001.