Dermatitis: The Different Types and How to Treat Each One

"Dermatitis" literally means inflammation of the skin. It's an umbrella term, not a single condition — and this is where confusion starts. When a doctor says "dermatitis," they could be referring to half a dozen different conditions that share the feature of red, inflamed, irritated skin but have very different causes and treatments.

Understanding which type of dermatitis you have is essential because treating seborrheic dermatitis like contact dermatitis (or vice versa) won't help — and might make things worse.

The Main Types

Atopic Dermatitis (Eczema)

What it is: A chronic condition driven by a compromised skin barrier and overactive immune response. It's the most common form of dermatitis and the one most people mean when they say "eczema."

What it looks like: Dry, itchy, inflamed patches. Can crack, weep, and crust. In lighter skin, patches are red. In darker skin, they may appear brown, purple, or gray.

Where it appears: Inner elbows, behind knees, hands, eyelids, neck. In adults, hands and face are commonly affected.

Key feature: Intense itching that drives the itch-scratch cycle. Associated with asthma and allergies (the "atopic triad").

Treatment:

• Daily moisturizing with ceramide-containing creams
• Topical corticosteroids for flares
• Calcineurin inhibitors (tacrolimus, pimecrolimus) for sensitive areas
• Dupilumab or JAK inhibitors for severe cases
• Avoiding known triggers

Contact Dermatitis

Contact dermatitis comes in two forms:

Irritant Contact Dermatitis

Caused by direct chemical damage to the skin. No allergy involved — it's purely a reaction to an irritating substance. Think harsh soap, detergent, bleach, prolonged water exposure, or friction.

• Affects anyone with enough exposure
• Appears right where the irritant contacted the skin
• Looks like redness, dryness, cracking, sometimes burning
• Most common in hands (occupational exposure)

Allergic Contact Dermatitis

A true immune-mediated allergic reaction to a specific substance. The immune system becomes sensitized after prior exposure, and future contact triggers inflammation.

Common allergens:

• Nickel (jewelry, belt buckles, snaps)
• Fragrances
• Preservatives in skincare (methylisothiazolinone, formaldehyde releasers)
• Poison ivy, oak, sumac (urushiol)
• Hair dye ingredients (PPD)
• Neomycin (antibiotic in OTC wound care products)
• Latex

What it looks like: Redness, swelling, blistering, weeping, and crusting — specifically in the area that contacted the allergen. The pattern often gives away the cause: a rash under a watch band (nickel), a rash on the eyelids (nail polish or cosmetic ingredient transferred by touch), a linear streak (poison ivy).

Treatment:

• Identify and avoid the allergen (patch testing can help identify the culprit)
• Topical corticosteroids for the acute rash
• Oral corticosteroids for severe or widespread reactions
• Cool compresses and barrier repair

Seborrheic Dermatitis

What it is: A chronic inflammatory condition associated with Malassezia yeast — the same organism involved in fungal acne and dandruff. In fact, dandruff is the mildest form of seborrheic dermatitis.

What it looks like: Greasy, yellowish scales on a red or pink base. Less dry-looking than eczema — more oily and flaky.

Where it appears: Areas with high sebaceous (oil gland) activity:

• Scalp (dandruff)
• Eyebrows
• Sides of the nose
• Behind and inside the ears
• Center of the chest
• Skin folds

Key feature: Tends to wax and wane. Worse during stress, cold weather, or illness. In infants, it's called "cradle cap."

Treatment:

• Antifungal washes (ketoconazole shampoo, zinc pyrithione)
• Topical antifungal creams (ketoconazole 2%)
• Low-potency topical corticosteroids for flares (hydrocortisone 1%)
• Calcineurin inhibitors for facial involvement
• Regular maintenance washing with antifungal products

Nummular Dermatitis (Discoid Eczema)

What it is: A distinct pattern of dermatitis that forms coin-shaped (nummular) patches on the skin. The cause isn't fully understood but is associated with dry skin and sometimes bacterial colonization.

What it looks like: Round or oval plaques, clearly defined, that can be weepy and crusted in the acute phase, then dry and scaly chronically. They can look remarkably like fungal infections (ringworm), and misdiagnosis is common.

Where it appears: Most common on the legs, forearms, and trunk. Often triggered by dry skin, skin injury, or insect bites.

Treatment:

• Aggressive moisturizing
• Topical corticosteroids (often need medium-to-high potency)
• Treating any secondary bacterial infection
• Avoiding skin drying (shorter, cooler showers)

Stasis Dermatitis

What it is: Inflammation of the skin on the lower legs caused by poor venous circulation. Blood pools in the veins, pressure builds, and the surrounding skin becomes inflamed.

What it looks like: Redness, swelling, itching, and scaling of the lower legs, usually around the ankles. Over time, the skin can darken (hemosiderin staining), become thickened, and develop open sores (venous ulcers).

Who it affects: Older adults, people with varicose veins, history of deep vein thrombosis, obesity, or prolonged standing.

Treatment:

• Compression therapy — the cornerstone of treatment (compression stockings)
• Leg elevation
• Topical corticosteroids for inflammation
• Wound care for ulcers
• Treating underlying venous insufficiency

Perioral Dermatitis

What it is: A distinct rash that occurs around the mouth, nose, and sometimes eyes. It's common in young women and is paradoxically often triggered by topical corticosteroids used on the face.

What it looks like: Clusters of small pink or red bumps and papules around the mouth, with a characteristic sparing of the skin directly around the lip border. Can be scaly and mildly burning.

Triggers:

• Topical steroids on the face (the most common cause — steroids help initially then make it worse when stopped)
• Fluoridated toothpaste
• Heavy face creams and cosmetics
• Inhaled corticosteroids (around the mouth)

Treatment:

• Stop all topical steroids on the face (this often causes initial worsening before improvement)
• Topical metronidazole or azelaic acid
• Oral antibiotics (doxycycline or minocycline) for more severe cases
• Simplified, gentle skincare

How to Tell Which Type You Have

A few guiding questions:

1. Where is it? Location narrows the differential significantly. Scalp with greasy flakes = seborrheic. Behind the knees with dry patches = atopic. Lower legs with swelling = stasis.

1. What does it look like? Greasy scales vs. dry scales vs. blisters vs. coin-shaped patches — the morphology matters.

1. When did it start and what was happening? New product, new jewelry, new medication, new stress, new environment — the timeline provides clues.

1. Does it itch? Atopic dermatitis itches intensely. Seborrheic dermatitis can itch but is often more annoying than unbearable. Contact dermatitis can itch or burn depending on the type.

1. Is there a pattern? Symmetrical vs. asymmetrical, localized vs. widespread, recurrent in the same spot vs. appearing in new areas.

When to See a Doctor

• Your rash isn't improving with over-the-counter treatments after 2 weeks
• It's spreading or getting worse
• You're not sure what type of dermatitis you have
• You suspect contact dermatitis but can't identify the trigger
• Your skin shows signs of infection (increasing pain, warmth, oozing, fever)
• The rash is affecting your sleep or daily function

At Coral Health, we can evaluate your skin through telehealth, identify the type of dermatitis you're dealing with, and prescribe appropriate treatment. Getting the type right is the most important step — everything else follows from there.

Different rashes need different solutions. Getting the right answer starts with the right question.