White ‘freckles’ on my arms – what are they?? 

White ‘freckles’ on my arms – what are they??

At the end of the summer, you may have noticed tiny white spots on your forearms and maybe also your shins.

These are called idiopathic #hypomelanosis guttate and are very common. In fact, they were likely already there before the summer, but often become more obvious with tanning).

The white spots are flat, usually smooth surfaced, and 2 to 5 mm in diameter.They are non-symptomatic, which means they not causing any symptoms such as pain or itchiness (ie you can only see them, but not feel them).

The good news is that (despite the scary sounding name…) idiopathic hypomelanosis guttate is completely harmless and non-symptomatic.

Actually, let me de-bunk the name for you.

– Hypomelanosis simply means lighter in colour than the surrounding skin

– Guttate means their shape resembles tear-drops (don’t read too much into that though – they are so small, they usually just look round to be honest…)

– Idiopathic means in general that a condition arises spontaneously and that there is essentially no known cause

So, hopefully now the latin name makes sense and doesn’t sound quite as intimidating. You actually get that a lot in dermatology – looooong latin names for something completely underwhelming…

I often see patients at Eudelo, who come to show me these, as they are concerned, they may suffer with #vitiligo. Idiopathic hypomelanosis guttate however is not to be mistaken for vitiligo. The latter is an autoimmune condition with white marks on the skin that look and behave distinctively different, so it’s nice to reassure patients with simple hypomelanosis guttate.

Hypomelanosis guttate lesions are particularly common in fair skin and have been connected to long-term sun exposure (a bit like sun freckles / age spots, but white instead of brown). They are seen as a normal part of the skin’s ageing process (hence more common in individuals over 40 years of age). You could say they are like greying of the hair.

They are usually found in sun-exposure skin of the shins and forearms, less often on face, neck and shoulders. Women are affected more than men.

Hypomelanosis guttate is harmless and there is no risk of these spots turning into a skin cancer. Topical vitamin A such as prescription tretinoin may slightly improve the appearance, but they generally don’t require treatment.

It’s hard to avoid them, if you have a genetic predisposition to get them (have you seen them in family members?), but daily application of a broad-spectrum SPF30-50 and avoidance of excessive sun exposure is certainly recommended and may lower the risk of developing these.

Hope this helps…

Yours truly,

Dr Stefanie