Second-To-Fourth Digit Ratio And Seborrheic Dermatitis In Males: A Cross-Sectional Study

In a 2019 cross-sectional study involving 100 males with seborrheic dermatitis and 100 healthy males, researchers found a significant correlation between the second-to-fourth digit ratio (2D:4D) and seborrheic dermatitis. The 2D:4D ratio, a marker of prenatal androgen exposure, was lower in males with seborrheic dermatitis, particularly in the right hand. The severity of seborrheic dermatitis was also negatively correlated with the 2D:4D ratio of the right hand. These findings suggest that a lower 2D:4D ratio could be a risk factor and predictor for the development of seborrheic dermatitis in males. However, the study had limitations, including a small sample size and patient selection from a single clinic.