How do they look different?

FeaturePerioral dermatitisPsoriasis
Typical appearanceClusters of small bumps, sometimes with tiny pustules or flaky skin.Raised, dry plaques, usually covered with silvery scale.
Typical locationAround the mouth, nose or eyes.Anywhere on the body or scalp.
SensationCan itch or burn, but sometimes causes neither.Can be very itchy, but sometimes causes no itch.
Useful clueA narrow strip directly beside the lips often stays clear.Plaques in skin folds can look shiny with little or no scale.
Contagious?No.No.
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Perioral dermatitis bumps can look red on light skin or skin coloured on darker skin. Dryness and flaking alone do not distinguish the two conditions. On the eyelids, psoriasis can cause dry patches with or without itching, while periorificial dermatitis can cause small raised bumps and pustules.34

When the rash affects openings other than the mouth, the more accurate name is periorificial dermatitis, because one facial rash apparently needs an extended edition of its name.1

Do they have the same cause?

The cause of perioral dermatitis is not fully understood. Possible triggers include topical steroids, thick moisturisers, cosmetics, inhaled or nasal steroids, and hormonal changes such as pregnancy. Psoriasis is an inherited condition in which skin cells reproduce and reach the surface too quickly, causing scaling. Throat infections, emotional stress and skin injuries can trigger psoriasis flares.12

What should you do about a rash around your mouth?

  1. 1Arrange an assessment if the diagnosis is unclear or the rash is not clearing. A dermatologist can examine the rash and choose treatment.
  2. 2Review any steroid cream you apply to the area. For suspected perioral dermatitis, stop hydrocortisone used without your doctor's knowledge. Ask the prescriber before stopping a prescription steroid or any other prescribed medicine.
  3. 3Wash gently with a mild, fragrance free cleanser. For perioral dermatitis, cleanse twice daily and avoid oil based facial creams; water based makeup and sunscreen are alternatives.
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Steroid creams can briefly improve perioral dermatitis before making it more extensive and inflamed. Stopping them can also cause a flare. Do not restart an unprescribed steroid to chase temporary relief. A dermatologist sometimes uses a milder steroid temporarily alongside other treatment, so follow the prescribed plan rather than changing it yourself.13

How is perioral dermatitis treated?

Some cases clear without medication; others need a prescription antibiotic or another treatment. Topical erythromycin, metronidazole or azelaic acid can help mild cases. Pregnancy changes antibiotic choices, so tell the prescriber if you are pregnant. Improvement is gradual, and complete clearing can take a few weeks to a few months.13

Where this answer comes from

  1. 1Follicular disorders. Perioral dermatitisdermnetnz.org
  2. 2Psoriasis: information for patients and familiesclinicalguidelines.scot.nhs.uk
  3. 3Red rash around your mouth could be perioral dermatitisaad.org
  4. 4Eyelid skin problemsdermnetnz.org