Can a diagnosis of molluscum contagiosum be made in the absence of umbilicated papules?

Can Molluscum Contagiosum Be Diagnosed Without Umbilicated Papules?

Yes, molluscum contagiosum can be diagnosed even when umbilication is not visible, particularly in early lesions, inflamed lesions, or atypical presentations, though umbilication remains the most distinctive diagnostic feature when present.

Understanding the Classic Presentation

The characteristic appearance of molluscum contagiosum includes skin-colored, whitish, or pink papules with a shiny surface and central umbilication 1, 2. However, this classic umbilicated appearance is not universally present in all cases or at all stages of disease evolution.

When Umbilication May Be Absent

Early or Nascent Lesions

• Papules develop umbilication as they mature and age 3
• Early lesions may appear as simple dome-shaped papules without the central depression 1
• This is why guidelines emphasize identifying and treating nascent lesions during initial examination 2, 4

Inflammatory Presentations

• Inflamed lesions may obscure the umbilication 5, 6
• Associated perilesional eczema, folliculitis, or secondary bacterial infection can mask the typical appearance 5, 7
• Excoriation from scratching can eliminate the central umbilication 6

Atypical Manifestations

• Immunocompromised patients may present with atypical lesions including giant, disseminated, necrotic, polypoidal, nodular forms, pseudocysts, or abscesses 5
• Multiple large lesions with minimal inflammation in HIV patients may not display classic umbilication 1, 2, 4

Diagnostic Approach When Umbilication Is Absent

Clinical Examination

• Look for shiny, dome-shaped papules even without umbilication 1
• Assess distribution pattern: trunk, face, and extremities in children; genital area in sexually active adults 3, 8
• Check for associated findings: conjunctivitis if near eyelids, perilesional eczema, or inflammatory reactions 1, 5

Dermoscopy

• Dermoscopy is superior to clinical examination alone and can identify diagnostic features even when umbilication is not clinically visible 6
• Look for yellowish-white polylobulated structures with peripheral telangiectasia 5
• Vascular patterns include crown (72%), radial (54%), and punctiform patterns (20%), with combinations possible 6
• Orifices are visualized in 97% of lesions by dermoscopy versus only 50% by clinical examination 6

Consider the Clinical Context

• Age and immune status matter: children, sexually active adults, and immunocompromised patients are most affected 2, 4, 8
• Transmission history: swimming pool attendance in children, sexual contact in adults, or known exposure 8
• Duration: lesions typically persist 6 months to 5 years without treatment 2, 4, 3

Common Pitfalls to Avoid

• Do not dismiss the diagnosis solely based on absent umbilication, especially in early, small, or inflamed lesions 5, 6
• Inflammatory manifestations can mimic other dermatological conditions and lead to unnecessary treatments if molluscum is not considered 5
• In cases with atypical presentations or diagnostic uncertainty, consider dermoscopy or referral to dermatology 2, 4, 5
• In immunocompromised patients with umbilicated papules, consider cryptococcal infection as a differential diagnosis, particularly in HIV patients 1

When to Confirm Diagnosis

If clinical and dermoscopic findings are equivocal, histopathological confirmation may be warranted, particularly in:

• Atypical presentations in immunocompromised patients 5
• Solitary lesions without classic features 8, 6
• Cases where differential diagnosis includes other serious conditions 1, 5