ConditionSkin, hair & nails
Dermatitis: Types, Causes and Treatment
Dermatitis means inflammation of the skin. It causes red or darker patches, itching, dryness, scaling, swelling and sometimes blisters or oozing. The main types are atopic dermatitis (eczema), contact dermatitis from irritants or allergens, seborrheic dermatitis (dandruff and greasy scaly patches), stasis dermatitis on the lower legs and light-triggered (phototoxic or photoallergic) dermatitis. Dermatitis is not contagious. Most types respond well to identifying triggers, moisturizing and anti-inflammatory creams.
Also called: Eczema, skin inflammation, eczematous dermatitis
At a glance
- What it is
- A general term for skin inflammation, often used interchangeably with eczema.
- Main types
- Atopic, irritant and allergic contact, seborrheic, stasis, dyshidrotic, nummular, perioral and phototoxic dermatitis.
- Common symptoms
- Itch, redness or darkening, dryness, scaling, swelling, blisters or oozing.
- Diagnosis
- Usually by appearance and history. Patch testing for contact allergy.
- Treatment
- Avoid triggers, moisturize, topical steroids or non-steroid creams, and specific treatments by type.
When to get help
Call 911 or go to the ER
- A widespread rash with skin peeling in sheets, blisters, sores in the mouth or eyes and fever, especially after a new medicine
- Swelling of the face, lips or throat or difficulty breathing
See a doctor within a day or two
- Painful, rapidly worsening eczema with clusters of punched-out sores or blisters (possible eczema herpeticum, a herpes infection)
- Oozing, yellow-crusted, hot or painful skin, or fever (possible bacterial infection)
- Red, swollen, painful lower legs with fever
Book a routine appointment
- A rash that keeps returning or has not improved after 2 weeks of home care
- A rash on the hands affecting work, or around the eyes
- Itching that disturbs sleep
- A suspected reaction to a product, plant or medicine
Usually safe to manage at home
- Mild dry, itchy patches that improve with fragrance-free moisturizers and avoiding irritants
- Mild dandruff controlled by medicated shampoo
Dermatitis vs eczema
The terms overlap. "Eczema" is often used for atopic dermatitis specifically, but dermatologists also use eczema and dermatitis interchangeably for inflamed, itchy skin of many types.
Types of dermatitis
| Type | Typical location | Key features |
|---|---|---|
| Atopic dermatitis | Elbow and knee creases, face, neck, hands | Chronic itch, dry skin, starts in childhood, linked to asthma and hay fever |
| Irritant contact dermatitis | Hands most often | Burning, dryness and cracking from soaps, water, solvents |
| Allergic contact dermatitis | Where the allergen touched | Itchy rash 1 to 3 days after contact with nickel, fragrance, poison ivy |
| Seborrheic dermatitis | Scalp, eyebrows, sides of nose, ears, chest | Greasy yellow scale, dandruff, cradle cap in babies |
| Stasis dermatitis | Lower legs, ankles | Brown discoloration, swelling, itch, from poor vein circulation |
| Dyshidrotic eczema | Palms, sides of fingers, soles | Tiny itchy blisters |
| Nummular eczema | Legs, arms | Coin-shaped itchy patches |
| Perioral dermatitis | Around the mouth, nose, eyes | Small red bumps, often after steroid creams |
| Phototoxic and photoallergic dermatitis | Sun-exposed skin | Rash triggered by light combined with a chemical or medicine |
Phototoxic dermatitis
Phototoxic dermatitis is a sunburn-like reaction that happens when a chemical on or in the skin absorbs UV light and damages skin cells. Anyone can get it with enough exposure. Common triggers:
- plants (phytophotodermatitis): lime juice, lemon, celery, parsnip, figs, giant hogweed. Typically after making drinks or gardening in the sun, causing streaky blisters and later dark marks
- medicines: doxycycline and other tetracyclines, fluoroquinolones, sulfonamides, thiazide diuretics, NSAIDs, amiodarone, voriconazole
- some fragrances containing bergamot oil
It appears within hours of sun exposure as redness, burning and sometimes blisters, often in odd shapes or streaks. It is followed by brown discoloration that can last weeks to months.
Phototoxic dermatitis treatment
- avoid further sun exposure until healed
- cool compresses and soothing moisturizers
- a medium-strength steroid cream for inflammation, as advised by a clinician
- pain relief with acetaminophen (paracetamol) or ibuprofen, following the label dose
- leave blisters intact and keep them clean
- review the medicine with your doctor and use strict sun protection while taking it
- wash hands after handling limes and other trigger plants before going in the sun
Photoallergic dermatitis is different: an allergic reaction that appears 1 to 3 days after exposure, is itchy and eczema-like, and can spread beyond exposed skin. See photodermatitis.
Causes and triggers
- genetic factors: filaggrin gene changes weaken the skin barrier in atopic dermatitis
- irritants: soaps, detergents, frequent handwashing, wet work
- allergens: nickel, fragrances, preservatives, plants
- climate: cold dry air, heat and sweating
- yeast: Malassezia in seborrheic dermatitis
- poor circulation in stasis dermatitis
- stress, which worsens many types
- light with certain chemicals or medicines
Symptoms
- itching, which can be intense
- redness on light skin, or purple, gray or dark brown patches on darker skin
- dry, scaly or cracked skin
- swelling
- small bumps, blisters, oozing and crusting in acute flares
- thickened, leathery skin from scratching (lichenification)
- lighter or darker patches after healing
Diagnosis
A doctor or dermatologist usually diagnoses dermatitis from its appearance, location and history. Additional tests include:
- patch testing for allergic contact dermatitis
- skin scraping to rule out fungal infection
- swabs if infection is suspected
- biopsy for unusual or persistent rashes
Treatment
Everyday skin care
- moisturize at least twice daily with thick, fragrance-free creams or ointments, especially after bathing
- use lukewarm water and soap-free cleansers
- pat dry, do not rub
- wear soft, breathable fabrics such as cotton
- keep nails short
Medicines
- topical corticosteroids: the main anti-inflammatory treatment, used in the right strength for the body area
- topical calcineurin inhibitors (tacrolimus, pimecrolimus) and topical PDE4 or JAK inhibitors for sensitive areas and long-term control
- antifungal shampoos and creams (ketoconazole) for seborrheic dermatitis
- compression stockings and leg elevation for stasis dermatitis
- antihistamines to help sleep
- phototherapy, dupilumab, other biologics and JAK inhibitor tablets for moderate to severe atopic dermatitis
- antibiotics only for proven infection
Outlook
Most dermatitis is manageable. Contact and phototoxic dermatitis clear once the trigger is avoided. Atopic and seborrheic dermatitis are chronic with flares, but good skin care and modern treatments keep most people comfortable.
Frequently asked questions
What is the difference between dermatitis and eczema?
Dermatitis means skin inflammation. Eczema is often used for atopic dermatitis, but the two words are frequently used interchangeably for itchy, inflamed skin. Contact, seborrheic and stasis dermatitis are all types of eczema in this broader sense.
What causes dermatitis?
Causes include an inherited weak skin barrier (atopic dermatitis), irritants such as soaps and water, allergens such as nickel and fragrance, yeast on the skin (seborrheic dermatitis), poor leg circulation (stasis dermatitis), and light combined with certain chemicals or medicines.
What is the treatment for phototoxic dermatitis?
Avoid further sun, use cool compresses and moisturizers, and apply a steroid cream if advised. Pain relievers help discomfort. Identify the trigger, such as lime juice or a photosensitizing medicine, and use strict sun protection. Dark marks fade over weeks to months.
Is dermatitis contagious?
No. Dermatitis is inflammation, not an infection, and cannot be passed to others. Scratched dermatitis can become infected with bacteria or herpes virus, which do need treatment.
How long does dermatitis last?
Contact and phototoxic dermatitis usually clear within 2 to 4 weeks once the trigger is avoided. Atopic and seborrheic dermatitis are long-term conditions that flare and settle, but can be well controlled with treatment.
Sources
This guide was written from current patient and clinical guidance, including:
- American Academy of Dermatology (AAD): Eczema types; Contact dermatitis
- National Eczema Association: Types of eczema
- NHS: Atopic eczema; Contact dermatitis; Seborrhoeic dermatitis
- MedlinePlus: Dermatitis
- National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS): Atopic dermatitis