popular names:

acne vulgaris, pimples, blackheads, comedo.

What is it?

Acne vulgaris or juvenile acne is one of the most prevalent dermatoses (skin disorders), affecting about 80% of the adolescents, but it may persist or begin in adulthood. Its a disorder of the pilo-sebaceous unit called pyoderma (hair and sebacious gland). The most severe conditions affect the male sex. As a rule, it manifests itself with moderate and discreet intensities. In some situations, the clinical manifestation is of such intensity that it reflects, aesthetically and socially, causing severe psychosocial damages and leading to social isolation and low self-esteem.

How does it develop?

There is a genetic predisposition which undergoes major changes due to hormonal, racial, environmental, emotional and bacterial factors, increasing or mitigating the clinical manifestations.

Evolution Factors

Ductal Hypercornification

Due to a genetic predisposition, a thickening (hypercheratinization) of the pilosebaceous follicle occurs, which combined with sebum forms a mass inside the follicle, generating a comedone, which can be open (blackhead) or closed (whitehead).

Increase of the seborrheic activity (sebum production), which is secondary to the increase in androgenic hormones.

Most involved microorganisms:

Propionibacterium acnes (P. acnes) e Staphylococcus epidermidis


Bacteria act on the sebum triggering the skin inflammation and forming painful, reddish, purulent lesions.

What does one feel?

Manifestations are multivariegated, appearing as:

papules (round, solid, erythematous, more elevated lesions)
pustules (when pus is observed)
nodules (deep, solid lesions) and abcesses
Most affected areas include: forehead, nose, chest and back. The most inflamed lesions can hurt or itch, and when they break they can drain a purulent discharge.

How does it look like?

Acne may manifest itself as non-inflammatory, in which there are only whiteheads and blackheads, and inflammatory acne. Classification of Acne

Type I – Comedonic acne


Presence of comedos, erythematous papules (reddish) and pustules

Type II – Papulo-pustular


Presence of comedos, erythematous papules (reddish) and pustules


Type III – Nodule-cystic acne

Presence of comedos, papules, pustules and cysts. Through the breaking of the follicle wall cysts are formed.


Type IV – Acne Conglobata


More severe than the former type. Cysts, on draining, form fistules (drainage 'tunnels') Forma mais grave do que o grau anterior. Os cistos, ao drenar, formam fístulas. ("túneis" de drenagem).


Grau V – Acne Fulminans.


Sudden onset accompanied by systemic symptoms (fever, leucocytosis, arthralgia…)

The therapeutic conduct is dependent on the degree of compromise.

How can it be prevented?

Acne markedly impacts the behaviour of the affected individual. Seeking treatment since the onset of the symptoms may prove critical in preventing scar formation and in best controlling the condition. Psychological support will help the patient to understand the facts and facilitates tretament adherence.

How is diagnosis done?

The diagnosis is clinical – medical consultation is ordinarily sufficient. More complex conditions require a specialist's advice.


Early treatment can help prevent scar formation, which in many cases may be more concerning than acne itself.