Whitehead

A whitehead is a closed comedone, and the only meaningful difference from a blackhead is whether the plug is open to the air. Here a thin layer of skin covers the top, so the contents never oxidise and never darken. The bump stays skin-coloured or slightly white, sits just under the surface, and is usually firm rather than tender.

Because it is sealed, a whitehead is more stubborn than a blackhead. Nothing can be extracted without breaking the skin over it, which is why squeezing one so reliably turns a bump that would have resolved into a mark that lasts months. The plug also sits in a closed environment where C. acnes can multiply, which is the route by which a quiet whitehead becomes an inflamed papule or pustule.

The treatment is the same as for any comedone, only slower. Retinoids are the mainstay because they change how skin cells shed and therefore stop the plug re-forming; salicylic acid helps but reaches a sealed comedone less easily than an open one. Expect eight to twelve weeks, not days, and expect an initial period where more of them surface as the deeper plugs are pushed up — the purge, which is different from a reaction.