What is axillary freckling?

Axillary freckling is the presence of flat, tan colored spots in the armpit area.  Axillary freckles are sometimes referred to as Crowe’s sign or café-au-lait macules and can be associated with a disease called neurofibromatosis type 1 (NF1).  Please see neurofibromatosis (or von Recklinghausen’s disease) for more information. This type of freckles can also be present in the groin area. Axillary freckles are present in about 20-30% of patients with NF1 and café-au-lait macules (not specific to the axilla) are present in 95% of those with NF1. 

Other syndromes associated with café-au-lait spots and axillary freckling include: McCune-Albright syndrome, Fanconi anemia, Tuberous sclerosis and Bloom syndrome to name a few.

What causes axillary freckling?

Axillary freckles are caused by an increase in melanin (skin pigment) content leading to a hyperpigmented lesion.

What is axillary freckling associated with?

Axillary freckling does not require treatment, however a diagnostic work-up should be done to diagnose any underlying condition, such as NF1.