When should a patient with severe eczema (atopic dermatitis) see an allergist?

When Should a Patient with Severe Eczema See an Allergist?

A patient with severe atopic dermatitis should be referred to an allergist when there is a strong clinical suspicion of allergic contact dermatitis (ACD) based on specific patterns or when food allergy is suspected as a trigger in moderate-to-severe disease that is not responding to first-line treatment. 1

Primary Indications for Allergist Referral

Contact Allergy Evaluation (Patch Testing)

Referral for patch testing should be considered when specific clinical patterns suggest allergic contact dermatitis:

• Facial and eyelid involvement that is disproportionately severe 1
• Increased severity at neck flexures 1
• Vesicular lesions on dorsal hands and fingertips 1
• Unusual distribution for typical atopic dermatitis (e.g., sides of feet) 1
• Persistent/recalcitrant disease not responding to standard atopic dermatitis therapies 1
• Disease aggravated by topical medications or emollients 1
• Later onset of disease or new significant worsening 1
• Absence of family history of atopy 1

The most common contact allergens in atopic dermatitis patients include nickel, neomycin, fragrance, formaldehyde and other preservatives, lanolin, and rubber chemicals. 1 A small subset may even develop allergic contact dermatitis to topical corticosteroids themselves. 1

Food Allergy Assessment

Do not refer for food allergy testing based on presence of atopic dermatitis or suspicious history alone. 1 Allergist referral for food evaluation is appropriate when:

• Consistent correlation between specific food intake and symptom flares documented in a food diary 1
• Moderate to severe disease with suspected food triggers 1
• Positive specific IgE to suspected foods (e.g., eggs in infants) combined with clinical correlation 1
• Improvement during diagnostic elimination diet requiring oral food challenge confirmation under allergist guidance 1

The true frequency of food allergies causing isolated atopic dermatitis flares is probably low, and there is frequent misattribution of flares to food-related issues. 1

When Allergist Referral is NOT the Priority

Refer to Dermatology First When:

• Failure to respond to first-line treatment with mildly potent steroids in children or moderately potent steroids in adults 1
• Diagnostic uncertainty about whether the condition is atopic dermatitis 1
• Need for second-line treatments such as phototherapy, systemic immunosuppressants, or biologics 1
• Severe disease requiring systemic therapy based on extent, severity scores, or quality of life impairment 1

Most patients with severe eczema will benefit more from dermatology referral than allergist referral, as the primary issue is typically disease severity rather than specific allergen triggers. 1

Important Caveats

• Patch testing sensitivity ranges from 60-80%, and positive tests only indicate contact sensitization—clinical relevance must be demonstrated through avoidance and resolution of corresponding dermatitis 1
• It is extremely rare to find one allergen responsible for atopic dermatitis, which is a complex multifactorial disease where non-allergic factors such as climate and secondary infection may be implicated 1
• Elimination diets should not be initiated empirically without proper allergy testing and clinical correlation 1
• If improvement occurs during elimination diet, oral food challenge under allergist supervision is essential for confirmation 1

Practical Algorithm

1. First, optimize topical therapy and ensure adherence before considering allergist referral 1
2. Assess for specific patterns suggesting contact allergy (facial predominance, unusual distribution, aggravation by topicals) 1
3. If contact allergy suspected: Refer to allergist for patch testing 1
4. If food allergy suspected: Document correlation with food diary, then refer to allergist only if consistent pattern emerges 1
5. If no specific allergic patterns but severe disease: Refer to dermatology for systemic therapy consideration 1