Acne and Rosacea Charity Training Manual

In some patients, comedones can be deep and so large that they totally
obliterate the skin pore. These are called macro-comedones (Figure 2).
These lesions do not respond to medical treatment and are often
responsible for the deeper nodular inflammatory lesions of acne.
Topical retinoids can loosen the blockage but the plug cannot get to
the surface. The only way of getting rid of them is to lightly cauterize the
surface of the skin which allows them to escape (see Module 4). Macrocomedones
are a contraindication to oral isotretinoin as they have the
potential to generate severe inflammatory lesions with the drug leading
to scarring.
Figure 2 – Macro-comedones
On the nose, the follicles are different to the follicles on general
glabrous skin often containing multiple hairs. With follicular hyper
cornification, the multiple hairs compound the follicular blockage
and blackheads are generally larger. This leads to a condition known
as Trichostasis spinulosa (Figure 3). Cosmetically this causes
problems and is more difficult to treat than normal comedones and
requires longer treatment with topical retinoids.
Figure 3 Trichostasis spinulosa