[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [General pathology](https://durgical.com/en/general-pathology/) › [Skin](https://durgical.com/en/general-pathology/areas/skin/) › Acne vulgaris and rosacea

# Acne vulgaris and rosacea

- Lesion

Acne starts in blocked oil glands in teenagers. Rosacea is facial flushing and pimples in adults, without blackheads.

Updated Nov 12, 2026

## Key points

- Acne: comedones (open = blackheads, closed = whiteheads) are the primary lesion; inflammatory papules, pustules, nodules, cysts.
- Four factors: keratin plug, androgens and sebum, C. acnes, inflammation (TLR2, IL-1).
- Triggers and associations: puberty, PCOS, androgenic drugs, glucocorticoids, lithium.
- Rosacea: middle-aged adults, flushing and erythema of central face, telangiectasias; no comedones.
- Rosacea mechanisms: innate immune overactivity (cathelicidin LL-37), neurovascular dysregulation, Demodex mites.
- Rhinophyma: sebaceous hyperplasia and fibrosis of the nose; ocular rosacea (blepharitis).

## What it is

Acne vulgaris is a disease of the pilosebaceous unit, nearly universal in adolescence, caused by four interacting factors: follicular hyperkeratinisation, androgen-driven sebum production, colonisation by Cutibacterium acnes and inflammation. Rosacea is a chronic disorder of facial vessels and follicles in adults, with flushing, persistent redness, papules and pustules, and in advanced cases tissue overgrowth of the nose (rhinophyma).

## Step by step

- Androgens enlarge sebaceous glands and increase sebum.
- Follicular keratinocytes adhere abnormally and plug the infundibulum: microcomedone.
- C. acnes thrives in the trapped sebum and releases lipases and pro-inflammatory molecules.
- Innate immune activation recruits neutrophils and lymphocytes.
- The follicle ruptures, sebum and keratin leak into the dermis: inflammatory nodule and scarring.

## Acne vs rosacea

| Feature | Acne vulgaris | Rosacea |
| --- | --- | --- |
| [Age](https://durgical.com/en/conditions/acne-vulgaris/) | Adolescents, young adults | Middle-aged adults |
| Comedones | Present (primary lesion) | Absent |
| Flushing | No | Yes, triggered by heat, alcohol, spicy food |
| Distribution | Face, chest, back | Central face |
| [Late changes](https://durgical.com/en/conditions/rosacea/) | Scars | Telangiectasias, rhinophyma |

## Clinical notes

- Retinoids act on keratinisation and sebum; antibiotics reduce C. acnes and inflammation.
- Severe nodulocystic acne scars and can affect mental health.

## Memory aid

Acne is a clogged chimney (comedone) with bacteria in the soot; rosacea is a face that blushes too often and keeps the blush.

## Test yourself

Think of the answer, then tap the question to see it.

## What are the four factors in acne pathogenesis?

Follicular hyperkeratinisation, increased sebum (androgens), C. acnes colonisation and inflammation.

## Which clinical feature separates rosacea from acne?

Rosacea lacks comedones and shows flushing and telangiectasia of the central face.

## What is rhinophyma?

Sebaceous hyperplasia, fibrosis and vessel dilation of the nose in advanced rosacea.

[Add to my cards (3)](https://durgical.app/estudiar/?add=/en/general-pathology/acne-vulgaris-and-rosacea/)

[More Pathology questions →](https://durgical.com/en/practice/?f=pathology)

## Elsewhere in DurgiPedia

- [Hair follicles, sebaceous and sweat glands, nails](https://durgical.com/en/histology/hair-follicles-sebaceous-and-sweat-glands-nails/)
- [Chronic inflammation: causes, cells and features](https://durgical.com/en/general-pathology/chronic-inflammation-causes-cells-and-features/)

## Connections

## Related 2

- [Skin pathology: terms and reaction patterns](https://durgical.com/en/general-pathology/skin-pathology-terms-and-reaction-patterns/)
- [Chronic inflammation: causes, cells and features](https://durgical.com/en/general-pathology/chronic-inflammation-causes-cells-and-features/)

## Related conditions 3

- [Acne vulgaris](https://durgical.com/en/conditions/acne-vulgaris/)
- [Rosacea](https://durgical.com/en/conditions/rosacea/)
- [Hidradenitis suppurativa](https://durgical.com/en/conditions/hidradenitis-suppurativa/)

[← All of general pathology](https://durgical.com/en/general-pathology/)

Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.

Sources: [Acne](https://medlineplus.gov/acne.html) (MedlinePlus, US National Library of Medicine, 2025); [Rosacea](https://medlineplus.gov/rosacea.html) (MedlinePlus, US National Library of Medicine, 2025).

## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake

Representative model, for educational purposes only.

---
Source: https://durgical.com/en/general-pathology/acne-vulgaris-and-rosacea/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/general-pathology/acne-vulgaris-and-rosacea/