What is dermatitis? What is eczema?
eczema are often used interchangeably. In some cases the term
eczematous dermatitis is used.
Dermatitis / eczema is actually a group of disorders with similar appearance, in which the surface of the skin is dry or blistered. The rash can be acute or chronic or a combination.
- Acute dermatitis / eczema refers to a rapidly evolving red rash which may be blistered and swollen.
- Chronic dermatitis / eczema refers to a longstanding irritable area. It is often darker than the surrounding skin, thickened (lichenified) and much scratched.
- Subacute dermatitis / eczema is an in-between state, usually red and dry skin
- Secondary findings include scratch marks (excoriation), thickened skin (lichenification) and secondary infection
Dermatitis affects about one in every five people at some time in their lives.
Acute dermatitis (allergy to adhesive plaster)
Subacute dermatitis (atopic eczema)
Chronic dermatitis (atopic eczema)
How is dermatitis diagnosed?
In most cases, dermatitis can be readily diagnosed by its clinical features; an itchy condition in which the skin surface is blistered or dry. However, sometimes a skin biopsy is performed to make or confirm the diagnosis.
The histology of dermatitis (or eczema) includes spongiosis and variable epidermal acanthosis with a superficial perivascular lympho-histiocytic infiltrate. The prominence of one or other feature differs according to how acute the rash is and its underlying cause.
Different forms of eczema/dermatitis are distinguished by age of onset, affected body sites, known causes and other clinical features. Biopsy is not helpful. Combinations can occur, especially in patients with atopy. The table below lists some common forms of dermatitis.
|Type of eczema||Age of onset||Body site||Known causes||Other features|
|Atopic dermatitis||Before 5 years in 90%||Depends on age:
|Seborrhoeic dermatitis||First year of life or post-adolesccence||
|Nummular dermatitis||Any age||
|Eczema craquele||Most often elderly||
|Venous eczema||Middle-aged to elderly||
|Contact dermatitis||Any age||Any especially:
|Lichen simplex||Mainly adults||
|Disseminated secondary eczema||Any||
||Localised inflammatory reaction
What is the treatment of dermatitis?
An important aspect of treatment is to identify and tackle any contributing factors (see above).
- Bathing Reduce how often you bath or shower, using lukewarm water. Showers are better. Replace standard soap with a substitute such as a mild detergent soap-free cleanser: your chemist or dermatologist can advise you.
- Clothing Wear soft smooth cool clothes; wool is best avoided.
- Irritants Protect your skin from dust, water, solvents, detergents, injury.
- Emollients Apply an emollient liberally and often, particularly after bathing, and when itchy. Ask your doctor or dermatologist to recommend some to try; avoid perfumed products when possible.
- Topical steroids Apply a topical steroid cream or ointment to the itchy patches for a 5 to 15 day course. A suitable one will be prescribed by your doctor or dermatologist. Make sure you understand when and where to apply it, and how often you may repeat the course. Steroids should usually be applied once or twice daily to the red and itchy areas only. Sometimes two or more topical steroids will be supplied, either for different parts of the body, or for differing grades of dermatitis.
- Pimecrolimus cream Pimecrolimus is a new anti-inflammatory cream shown to be very effective for atopic dermatitis, with fewer side effects than topical steroids.
- Antibiotics Your doctor will recommend antibiotics such as flucloxacillin or erythromycin if infection is complicating or causing the dermatitis. The infection is most often with Staphylococcus aureus or Streptococcus pyogenes.
- Antihistamines Antihistamine tablets may help reduce the irritation, and are particularly useful at night.
- Other treatments Systemic steroids, methotrexate, azathioprine, phototherapy, and other complicated treatments may also be used for severe cases.
Long term control of eczema/dermatitis
Dermatitis is often a long-term problem. Treat dry skin with moisturisers and avoid the use of soap. If the itchy rash returns, use both the moisturiser and the steroid cream or ointment. If it fails to improve within two weeks, see your doctor for further advice.
On DermNet NZ:
- Atopic dermatitis
- Nummular dermatitis
- Seborrhoeic dermatitis and dandruff
- Hand dermatitis
- Irritant contact dermatitis
- Allergic contact dermatitis
- Patch testing
- Dermatitis online course for health professionals
- Sensitive skin
- Dermatitis – BMJBestTreatments; free access for New Zealanders subsidised by Ministry of Health
- Eczema – Medline Plus
- Allergy New Zealand: local support group
- National Eczema Association for Science and Education: an American patient support organisation
- EczemaNet: American Academy of Dermatology
- Eczemavoice: discussion board
- Dermatitis – various chapters in Medscape Reference
- Eczema – emedicinehealth
- Patient information: Contact Dermatitis (The Basics) – UpToDate (for subscribers)
- Eczema / skin reactions – AHA! Swiss Allergy Centre
See the DermNet NZ bookstore