Papules often appear to arise on clinically normal skin, but in almost all cases, a closed comedo was previously present. The lesions are an average of about 4 mm in diameter. If papules do not evolve into pustules, they resolve, leaving an erythematous macule and, ultimately, normal skin or an abnormally pigmented macule. Pustules may be tender and surmount an erythematous papule or macule. Superficial pustules usually run their course and dry up in less than a week.
Deep pustules are more common in patients with more severe cases of acne.
These lesions are almost always tender and take two to six weeks to resolve. As papules and pustules resolve, they may leave areas of hyperpigmentation and hypopigmentation that are of special cosmetic significance in dark-skinned patients. Areas of hyperpigmentation may require more than a year to resolve. Although scarring is usually associated with deeper nodular and cystic lesions, scarring may also be a sequela of less inflammatory, more superficial papules and pustules. Nodules are very deep seated lesions that are often 1 cm or larger in diameter and that vary in consistency from firm to fluctuant.