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[8 min read] Rosacea: Pathophysiology and presentation
Rosacea affects around 415 million people worldwide, and is particularly common in women over 30. As a primary care physician, how much do you know about the pathophysiology and presentation of this skin condition?
What is rosacea?
Rosacea is a chronic condition characterised by redness or flushing on the face, particularly the forehead, nose, cheeks and chin. Clinical symptoms include erythema, telangiectasia and an inflammatory papulopustular eruption similar to acne.
Typically, symptoms don’t appear until after 30 years of age. Flare-ups usually last for at least three months at a time, and symptom frequency can increase as patients get older. People of European decent with fair skin are most often affected by this common condition.
Experts from the National Rosacea Society outlined characteristics of four different subtypes of rosacea:
- Erythematotelangiectatic: The most predominant symptom of this subtype of rosacea is central facial flushing often accompanied by stinging or burning.
- Papulopustular: This is the classic subtype of the disease. The predominant symptom consists of a reddening in the centre of the face with small erythematous papules surmounted by pinpoint pustules.
- Phymatous: Common symptoms of this rosacea subtype include thickening of the skin and irregular surface nodularities of the forehead, eyelids, nose, chin, and/or ears.
- Ocular: Typical manifestations of this subtype are blepharitis and conjunctivitis, along with inflammation of the lids and meibomian glands, interpalpebral conjunctival hyperemia, and conjunctival telangiectasias.
The latest recommendations require one diagnostic or two major phenotypes to diagnose rosacea.
Specific clinical signs and symptoms define each subtype, but importantly, subtypes can occur simultaneously, and one subtype can progress to a different subtype.
Dietary factors, such as alcohol, hot beverages, caffeine and spicy foods, can trigger the clinically relevant exacerbations of facial flushing and burning. In addition, some medications such as amiodarone and topical and nasal steroids, as well as high doses of vitamins B6 and B12, have been associated with symptom flare-ups.
Vasculature factors are thought to play a role in the pathogenesis of rosacea. One theory is that vasodilation of cutaneous blood vessels in the face is associated with the classic symptoms of redness and flushing.
The diagnostic cutaneous phenotypes for rosacea are fixed centrofacial erythema in a pattern that may become exacerbated (and persist for longer than three months) or phymatous changes.
The following are major phenotypes, of which two must be present to diagnose rosacea when a diagnostic phenotype is lacking: (1) papules and pustules; (2) frequent and prolonged flushing; (3) telangiectasia; or (4) ocular manifestations.
Burning, stinging, oedema, and dryness are secondary phenotypes. Skin biopsies may be used to rule out other diseases, but they are not required for rosacea diagnosis.
Some of the signs of rosacea that distinguish it from acne are:
- Dry and peeling skin
- Lack of comedones
- Little to no scarring
The development of rhinophyma is possible in isolated incidents of rosacea even without other signs or symptoms. However, rhinophyma is not associated with acne. Rhinophyma is more common in men than in women.