VisualDx - Diagnosis Details - Cellulitis DDx Arm: Dermatitis, Atopic

Last Updated: 06/29/2010

691.8 – Other atopic dermatitis and related conditions

Atopic dermatitis is also known as atopic eczema. It is a condition primarily affecting allergy prone people (often with atopic triad of eczema, allergic rhinitis, and asthma). The exact cause of the condition is unknown; however, most patients have marked xerosis and an inability to retain moisture in the skin. Atopy is defined by many to include the presence of allergen-specific immunoglobulin E. The clinical presentation ranges from weeping and crusted areas of eczema to papules or lichenified plaques. Infants and children are most frequently affected, but the condition may persist into adulthood.

There is no known cure for atopic dermatitis. Environmental triggers such as heat, low (or high) humidity, detergents/soaps, abrasive clothing (wools), chemicals, and smoke along with stress aggravate this disorder. The disorder is associated with intense itching that is aggravated by scratching. Scratching increases the chances of cutaneous infections because it produces breaks in the skin. Patients with atopic dermatitis are more prone to impetiginization with Staphylococcus aureus and infection with herpes simplex virus (HSV), eczema herpeticum.

Atopic dermatitis can be differentiated from cellulitis on the basis of itching, scaling, and distribution. Atopic dermatitis is often observed bilaterally and in multiple body locations.

Look For

Thickened, scaly, erythematous papules and plaques involving the flexural surfaces. Lesions are most prominent on the face, neck, antecubital fossae, popliteal fossa, and extremities in general. Impetiginized plaques can develop thick crusts. Blacks frequently have extensive follicular accentuation and shininess without obvious lichenified plaques.

Diagnostic Pearls

Make sure to obtain an adequate childhood and family history of allergies and skin disease. In the adult, persistent dry skin or persistent eyelid dermatitis may be a clue to atopic dermatitis.

Differential Diagnosis & Pitfalls

Allergic contact dermatitis
Irritant contact dermatitis
Nummular dermatitis (nummular eczema)
Tinea corporis
Psoriasis
Cellulitis or erysipelas
Lichen simplex chronicus
Ichthyosis vulgaris
Scabies
Pityriasis rubra pilaris
Cutaneous T-cell lymphoma / mycosis fungoides – If an adult patient has persistent "eczema" that is not adequately responding to therapy, this entity should be ruled out with skin biopsies.

In children in particular, consider Wiskott-Aldrich syndrome, selective IgA deficiency, Letterer-Siwe disease, hyper IgE syndrome, and Netherton syndrome, as these conditions may display similar eruptions.

Best Tests

Take a careful history, as this is primarily a clinical diagnosis.

In a few select cases, the following investigations may help rule out imitators:

Skin biopsy
Serum immunoglobulin levels (IgE, IgA, IgM, IgG); serum IgE level is elevated in 80% of patients
Oral food challenges, RAST, or skin allergy testing
HIV test

Management Pearls

Secondary bacterial infection may exacerbate atopic dermatitis. Treat with a 10-day course of oral antibiotics to cover S. aureus infection.

Counsel patients on the typical triggers and encourage their avoidance. Factors that are known to exacerbate atopic dermatitis include stress, inappropriate bathing habits, infection, irritants such as detergents, sweating, and environmental and food allergens.

Emollients and moisturizing skin care routines are essential. Recommend non-soap cleansers such as Cetaphil® or moisturizing soaps such as Dove®. Have the patient apply emollients such as petroleum jelly, Aquaphor® ointment, Eucerin® cream, and Cetaphil® cream to damp skin after bathing.

Refer chronic, recalcitrant, or severe cases to a dermatologist.

Therapy

Use topical corticosteroids to treat active, inflamed plaques. Use class 6–7 topical steroids on the face and mid- to high-potency preparations on the trunk and extremities. Be careful of atrophy from use in skin folds and occluded areas. Patients frequently become sensitive to a component of topical medications. Try to use ointments, as these usually contain fewer preservatives and stabilizers.

Localized disease:
Mid-potency topical corticosteroids (class 3–4) need supervision with scheduled follow-up to observe for steroid atrophy.

Triamcinolone cream, ointment (Kenalog®, Aristocort®) – apply twice daily (15, 30, 60, 120, 240 gm)
Mometasone cream, ointment (Elocon®) – apply twice daily (15, 45 gm)
Fluocinolone cream, ointment (Synalar®) – apply twice daily (15, 30, 60 gm)

Use low-potency topical steroids on thinner skin areas of the face and intertriginous areas.
Desonide (DesOwen®) or Aclovate® ointment or cream twice daily 30 gm twice daily.
Or
Tacrolimus ointment 0.03%, 0.1% twice daily.
Or
Pimecrolimus 1% cream twice daily.

Extensive disease:
UVB light therapy, PUVA or UVA I may be used. Reserve low doses cyclosporin A (100 mg/day) or FK506 (1–3 mg/day) for resistant disease. Narrow band UVB is an emerging therapy.

Antihistamine therapy is a critical component of treatment. Consider one of the following antihistamines:

Diphenhydramine hydrochloride (Benadryl®) (25, 50 mg tablets or capsules) 25–50 mg nightly or every 6 hours as needed
Hydroxyzine (Atarax®) (10, 25 mg tablets) 12.5–25 mg, every 6 hours as needed
Cetirizine hydrochloride (ZYRTEC®) (5,10 mg tablets) 5–10 mg per day
Loratadine (Claritin®) (10 mg tablets and RediTabs®) 10 mg tablet or RediTab once daily

Antibiotic therapy is beneficial when there is evidence of impetiginization. Direct coverage toward S. aureus. Direct coverage toward S. aureus. The literature has shown that in children bleach baths (1/4 to 1/2 cup Clorox® bleach diluted in a full bath tub of water before the child enters the tub) 1–3 times weekly may be useful in patients with multiple open areas (excoriations) or a history of multiple superinfections. Adults with atopic dermatitis who are prone to S. aureus infections may benefit from bleach bath therapy.

References

Huang JT, Abrams M, Tlougan B, Rademaker A, Paller AS. Treatment of Staphylococcus aureus colonization in atopic dermatitis decreases disease severity. Pediatrics. 2009 May;123(5):e808-14. PubMed Id: 19403473

Brenninkmeijer EE, Schram ME, Leeflang MM, Bos JD, Spuls PI. Diagnostic criteria for atopic dermatitis: a systematic review. Br J Dermatol. 2008 Apr;158(4):754-65. PubMed Id: 18241277

Leung DY, Eichenfield LF, Boguniewicz M. Atopic Dermatitis (Atopic Eczema). In: Fitzpatrick TB, Wolff K, eds. Fitzpatrick's Dermatology in General Medicine. 7th ed. New York, NY: McGraw-Hill; 2008:146-158.

Williams HC. Clinical practice. Atopic dermatitis. N Engl J Med. 2005 Jun 2;352(22):2314-24. PubMed Id: 15930422

Ashcroft DM, Dimmock P, Garside R, Stein K, Williams HC. Efficacy and tolerability of topical pimecrolimus and tacrolimus in the treatment of atopic dermatitis: meta-analysis of randomised controlled trials. BMJ. 2005 Mar 5;330(7490):516. PubMed Id: 15731121

Hanifin JM, Cooper KD, Ho VC, Kang S, Krafchik BR, Margolis DJ, Schachner LA, Sidbury R, Whitmore SE, Sieck CK, Van Voorhees AS. Guidelines of care for atopic dermatitis, developed in accordance with the American Academy of Dermatology (AAD)/American Academy of Dermatology Association "Administrative Regulations for Evidence-Based Clinical Practice Guidelines". J Am Acad Dermatol. 2004 Mar;50(3):391-404. PubMed Id: 14988682

Associated Findings

Appearance
No Acute Distress

Body Location
Abdomen
Antecubital Fossa
Anterior Lower Leg
Anterior Neck
Arm
Cheek
Chest
Eyelids
Face
Forearm
Inferior Eyelid
Labia Majora
Lateral Neck
Leg
Neck
Popliteal Fossa
Superior Chest
Superior Eyelid
Thigh
Upper Back

Configuration
Confluent
Follicular Configuration

Distribution
Bilateral
Diaper Area
Flexural
Scattered Haphazard
Widespread

Lesion
Blanching Patch
Erythroderma
Excoriated
Excoriation
Eyelid Edema
Lichenified Plaque
Plaque
Scale Fine
Scaly Papule

Occupations
Military

Signs and Symptoms
Lymphadenopathy
No Fever (Afebrile, Apyrexial)
Pruritus (Itching)

Social History
Elementary School (K-5)
Middle/High School (6-12)

Temporal
Developed Acutely Over Days to Weeks
Developed Chronically Lasting Months to Years
Developed Steadily Over Weeks to Months
Recurring Episodes or Relapses

Medical History
Allergic Rhinitis
Asthma
Blepharitis, Angular
Conjunctivitis, Allergic
Darier's Disease
Down's Syndrome
Ichthyosis Vulgaris
Lymphoma, Cutaneous T-Cell (Mycosis Fungoides, CTCL)
Pemphigus Benign Familial
Pemphigus Foliaceus

Authors
Tara Mahar MD, Art Papier MD