Workup for Immunocompromised State in Children with Molluscum Contagiosum
When to Consider Immunodeficiency Screening
Most children with molluscum contagiosum are immunocompetent and require no workup for immunodeficiency. 1, 2 However, specific clinical features should trigger evaluation for an underlying immunocompromised state.
Red Flags Requiring Immunodeficiency Evaluation
Screen for immunocompromised state when the following features are present:
- Multiple large lesions with minimal or absent inflammatory response - this atypical presentation suggests impaired immune recognition of the virus 1, 2
- Giant molluscum lesions (typically >1 cm in diameter) - while rare cases occur in healthy children, this finding warrants consideration of immune evaluation 3
- Extensive or disseminated disease that is recalcitrant to standard treatments 1
- Atypical morphology including necrotic, polypoidal, nodular forms, pseudocysts, or abscesses without classic umbilication 1
- Persistent disease beyond the typical 6-12 month self-resolution period in the absence of reinfection 4, 5
Recommended Workup Algorithm
When red flags are present, the following evaluation is appropriate:
- HIV testing - molluscum contagiosum occurs in 3-4% of HIV-infected children in the United States and is a recognized opportunistic infection in this population 6
- Complete blood count with differential - to assess for lymphopenia or other hematologic abnormalities suggesting immunodeficiency
- Immunoglobulin levels (IgG, IgA, IgM) - to evaluate for humoral immunodeficiency
- Consider referral to immunology for comprehensive immune evaluation if initial screening is abnormal or clinical suspicion remains high 1
Important Clinical Context
- Standard molluscum presentations do not require workup - typical dome-shaped, umbilicated papules in otherwise healthy children with normal disease course need no immunodeficiency evaluation 1, 2
- Geographic and demographic considerations - giant molluscum has been reported in healthy African immigrant children without underlying immunodeficiency, so clinical judgment is essential 3
- Conjunctivitis alone is not a red flag - periocular lesions commonly cause follicular conjunctivitis in immunocompetent children and this does not indicate immunodeficiency 1, 2
Pitfalls to Avoid
- Do not routinely screen all children with molluscum - the vast majority are immunocompetent and screening is not cost-effective or clinically indicated 4, 7
- Do not delay treatment while awaiting workup - physical removal of lesions should proceed regardless of immune status, as reducing viral load helps the immune system clear residual virus 1, 2
- Do not confuse perilesional eczema or inflammatory response for immunodeficiency - erythema around lesions typically represents normal immune recognition and clearance 1