Geography and Education Shape Diagnostic Delay in Hidradenitis Suppurativa

Delays in hidradenitis suppurativa (HS) diagnoses are a familiar problem, but access to care may be only part of the story. A 2026 study in Skin Health and Disease found that where patients lived and their educational attainment were independently associated with time to HS diagnosis. Some of those relationships ran counter to conventional assumptions about socioeconomic advantage and healthcare access.

Investigators at the University of California, San Francisco conducted a cross-sectional analysis of patients with HS enrolled in a longitudinal cohort between 2016 and 2020. Rather than treating socioeconomic status (SES) as a single characteristic, they examined 4 dimensions: educational attainment, insurance type, neighborhood SES, and rural-urban geography.

The analysis included 196 patients with complete data. Median age at the baseline visit was 34.5 years, and 75% were female. The cohort was racially and ethnically diverse, although it skewed toward socioeconomic advantage: 45.9% had at least a bachelor's degree, and nearly two-thirds lived in neighborhoods within the 2 highest SES quintiles.

Time to diagnosis was calculated from patient-reported age at symptom onset and age at diagnosis. Overall, patients waited a median of 4.5 years, with an interquartile range of 1.5 to 13 years.

Geography Emerged as an Independent Barrier
Patients living in metropolitan areas with more than 1 million residents had a median diagnostic interval of 4 years. For those living in smaller metropolitan areas or nonmetropolitan communities, the median reached 7.5 years.

The difference persisted after adjustment for age at onset, sex, race and ethnicity, education, insurance, and neighborhood SES. Living outside a metropolitan area with more than 1 million residents was associated with a 73% longer time to diagnosis (exponentiated coefficient, 1.73; 95% CI, 1.04-2.87).

The authors point to dermatologist availability as one potential explanation. Because HS diagnosis often depends on clinical recognition and dermatologic expertise, lower specialist density and less familiarity with HS among generalists could contribute to longer diagnostic pathways outside large urban centers. This finding supports efforts not only to expand dermatology access, but also to improve HS recognition among clinicians practicing in communities with limited specialist availability.

Education Produced a Less Intuitive Pattern
Educational attainment showed the opposite association from what might be expected. Patients with less than a bachelor's degree had a median time to diagnosis of 3.5 years, compared with 7 years among those with a bachelor's degree or higher.

After full adjustment, time to diagnosis among patients with less than a bachelor's degree was 53% shorter than among those with higher educational attainment (exponentiated coefficient, 0.47; 95% CI, 0.32-0.69). Insurance type and neighborhood SES, meanwhile, were not independently associated with diagnostic timing.

Why greater educational attainment tracked with a longer delay remains uncertain. The investigators raise several possibilities, including unmeasured geographic differences in access to dermatologists. They also suggest that greater health literacy could potentially lead some patients to consider alternative explanations for early symptoms before seeking HS-specific care. However, these remain hypotheses.

Diagnostic Delay Did Not Track with Hurley Stage
Longer time to diagnosis was not independently associated with moderate-to-severe disease, defined as Hurley stage II or III. That finding should be interpreted carefully. Hurley stage was recorded at the study baseline visit rather than at diagnosis, and some participants had already received HS treatment by then, limiting the ability to determine whether diagnostic delay influenced disease progression.

Other constraints reinforce the need for caution. Diagnostic timing depended on patient recall, and 23% of participants reported symptom onset and diagnosis within the same integer year. Socioeconomic measures and disease severity were assessed at baseline rather than necessarily reflecting conditions when symptoms first appeared. The single-center dermatology cohort also excluded uninsured patients and may underrepresent individuals facing the greatest barriers to diagnosis.

Still, the findings broaden the discussion around HS diagnostic delay. Access disparities may not follow a simple socioeconomic gradient, and geography appears particularly relevant. Larger studies representing a wider socioeconomic spectrum could help determine which barriers are most amenable to intervention and whether shortening the diagnostic pathway ultimately changes HS severity or long-term outcomes.

Reference:
Chang AY, Supapannachart KJ, Boscardin J, Yazdany J, Naik HB. Socioeconomic factors and time to diagnosis in hidradenitis suppurativa. Skin Health Dis. 2026;6(4):631-634. Published July 1, 2026. doi:10.1093/skinhd/vzag095