What is the best treatment approach for an 8-year-old patient with nodular lesions on the extensor surface?

Management of Nodular Lesions on Extensor Surfaces in an 8-Year-Old

For an 8-year-old with nodular lesions on the extensor surface, the most likely diagnosis is erythema nodosum (EN), which should be treated by addressing the underlying inflammatory condition with systemic corticosteroids if symptoms are significant, while topical corticosteroids can be used for mild cases. 1

Clinical Recognition and Diagnosis

Erythema nodosum presents as raised, tender, red or violet subcutaneous nodules of 1–5 cm in diameter that commonly affect the extensor surfaces of the extremities, particularly the anterior tibial areas 1. The diagnosis is clinical and based on characteristic features:

• Nodule characteristics: Raised, tender, subcutaneous nodules with red or violet discoloration 1
• Location: Predominantly on extensor surfaces, especially anterior tibial areas 1
• Size: Typically 1–5 cm in diameter 1

Biopsy is not usually appropriate when clinical features are characteristic, though if performed would show non-specific focal panniculitis 1. The key is to exclude other specific skin disorders through clinical assessment 1.

Differential Diagnosis Considerations

In the context of inflammatory bowel disease (which can occur in children), the differential includes:

• Metastatic Crohn's disease: May appear as solitary or multiple nodules, plaques, ulcers, or violaceous perifollicular papules, with histology showing non-caseating granulomas 1
• Sweet's syndrome: Tender, red inflammatory nodules or papules, usually affecting upper limbs, face or neck, distinguished by appearance, distribution and histological features 1

Treatment Algorithm

First-Line Management

Topical corticosteroids should be the first-line treatment for localized lesions 1:

• Apply a thin film of mid-potency topical corticosteroid (such as alclometasone dipropionate) to affected areas 2-3 times daily 2
• Massage gently until medication disappears 2
• Safe for use in children ≥1 year of age 2
• Continue until control is achieved; reassess if no improvement within 2 weeks 2

Systemic Treatment Indications

Systemic corticosteroids are usually required when 1:

• Lesions are widespread or severely symptomatic
• Topical therapy fails to provide adequate relief
• Underlying inflammatory condition is active

The treatment is fundamentally based on addressing any underlying condition, as EN is closely related to disease activity 1.

Resistant or Recurrent Cases

For resistant cases or frequent relapses, consider 1:

• Immunomodulation with azathioprine as second-line therapy 1
• Anti-TNF agents (infliximab or adalimumab) for refractory cases 1

Critical Pitfalls to Avoid

Topical Corticosteroid Use in Children

• Do NOT use in the diaper area if the child still requires diapers, as these constitute occlusive dressing 2
• Avoid occlusive dressings unless specifically directed by a physician 2
• Do NOT use on face, underarms, or groin unless specifically indicated 2
• Limit duration: Safety and efficacy beyond 3 weeks have not been established in children 2
• Monitor for HPA axis suppression in children, who are more susceptible to systemic toxicity due to larger skin surface area to body mass ratios 2

Monitoring Requirements

• Discontinue therapy when control is achieved 2
• If no improvement within 2 weeks, reassess diagnosis 2
• Watch for signs of local adverse reactions including skin atrophy, irritation, or allergic contact dermatitis 2
• If concomitant skin infections develop, use appropriate antifungal or antibacterial agents 2

Application Technique

Proper application method 2, 3:

• Apply thin film only—multiple daily applications do not lead to better or faster resolution 3
• Massage gently until medication disappears 2
• 2-3 times daily application is sufficient 2
• Intermittent therapy with treatment-free intervals can be as effective as continuous treatment 3

When to Escalate Care

Refer or escalate treatment if 1:

• No response to topical corticosteroids within 2 weeks
• Lesions are associated with systemic symptoms suggesting underlying inflammatory disease
• Recurrent episodes despite appropriate treatment
• Suspicion of alternative diagnosis requiring biopsy