Hypopigmented macules are seen in a variety of disorders and the diagnosis rests on clinicopathological correlation. However, some cases are difficult to classify and pose a diagnostic challenge.

The goal of a new study published in the Indian Journal of Dermatology, Venereology and Leprology described the clinical and histopathological features of patients with hypopigmented macules and follicular spongiosis on histopathology.

This was a retrospective analysis of clinical and histopathological findings in 12 patients who presented with clinically nondiagnostic hypopigmented macules and showed follicular spongiosis on skin biopsy – between January 2015 and October 2016. The findings were compared with 12 patients with "unclassified" hypopigmented macules, who did not show follicular spongiosis on skin biopsy.

Overall, 12 patients with hypopigmented macules were detected with spongiosis affecting the follicular epithelium, on histopathology. Among these were eight men and four women—most in their second decade of life—presenting with hypopigmented macules most commonly on the upper limbs, for a mean duration of 6.33 ± 5.10 months. Clinically evident lesional hair loss was noted in all patients, and follicular prominences in seven (58%) patients. Meanwhile, histological features suggestive of other diagnosis – namely leprosy, mycosis fungoides or sarcoidosis were not seen in any biopsy. Alcian blue stain revealed minimal amount of mucin in one biopsy. Clinically apparent hair loss and follicular prominences were found to be statistically significantly associated with histological evidence of follicular spongiosis.

The findings indicated that patients with hypopigmented macules and follicular spongiosis on histopathology may represent a distinct clinicopathological entity – associated with lesional hair loss and follicular prominences. It was stated that this is probably a variant of an endogenous dermatitis similar to pityriasis alba.

Source: Indian Journal of Dermatology, Venereology and Leprology. Jul-Aug 2020;86(4):386-391. doi: 10.4103/ijdvl.IJDVL_679_17.