DISCUSSION
Only one English study has described multiple papular lesions on an erythematous background as the dermoscopic finding of follicular mucinosis 3. In the present case, the histopathological finding of mucin deposits in the follicular infundibulum and isthmus appear to correspond to the dermoscopic findings of brownish yellow dots in the follicular ostium. Also, the histopathological findings of dilated capillary vessels appear to correspond to the dermoscopic findings of red dots in the interfollicular area.
Yellow dots are a trichoscopic finding that corresponds to a dilated follicular infundibulum filled with keratotic material and/or sebum. They are observed as rounded or polycyclic structures with colors ranging from pinkish yellow to brownish yellow 4. This finding has been subsequently detected in various diseases, such as alopecia areata, chronic cutaneous lupus erythematosus, androgenetic alopecia, dissecting cellulitis, and, less frequently, trichotillomania5. Therefore, brownish yellow dots in the present case are not specific to follicular mucinosis.
Red dots are a dermoscopic finding that corresponds to dilated vessels aligned perpendicular to the skin surface 6. This finding has been subsequently detected in melanocytic lesions such as melanoma and melanocytic nevus as well as inflammatory diseases such as psoriasis 6. Therefore, red dots in the present case are not specific to follicular mucinosis. In that context, the combination of both brownish yellow dots and red dots appears to be non-specific. However, this case report suggests that dermatologists should consider the possibility of follicular mucinosis when such dermoscopic findings are obtained.