Acne Inversa vs. Folliculitis: What Is the Difference?

Written by Dr. rer. nat. Dennis Alexander Kwiatkowski

Why both terms come up

Folliculitis means that hair follicles are inflamed. It can look like small pimples or pustules on hairy skin. Early acne inversa can also begin with inflamed nodules. As a result, both are quickly placed in the same category in everyday life.

Medically, it matters more precisely what the lesions look like and how they behave over time.

What is more consistent with folliculitis

Folliculitis often presents with smaller papules or pustules centred around hair follicles. It may itch, burn, or be tender to the touch. Depending on the cause, it can appear at different hairy body sites.

This does not mean folliculitis is always harmless. It only means that its typical appearance does not automatically signify an HS diagnosis.

What looks different in HS

Acne inversa comes more into focus when symptoms:

• are located deeper and are clearly painful,
• recur as nodules or abscesses,
• concentrate in typical skin-fold regions,
• open up, weep, or leave scars,
• develop indurations, recurring openings, or tunnels (sinus tracts).

A few superficial pustules and a recurring deep nodule are different observations. It is precisely this distinction that helps at the appointment.

The course also plays a role

Folliculitis and HS can present similarly at individual sites. Even the groin or armpit is not automatic proof of HS. What matters is whether a medical professional recognises a recurring HS pattern: typical lesions, typical locations, and a chronic or recurrent course.

If the skin happens to be calmer at the appointment, notes or photos of active episodes can help describe the course more accurately.

When you should have it evaluated

Recurring painful nodules in typical HS regions should be assessed by a dermatologist, even if earlier episodes were labelled as folliculitis. In the event of rapid deterioration, fever, or sharply increasing pain, prompt medical help is needed.