11/14/24, 10\:55 AM Molluscum contagiosum

Molluscum contagiosum

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A comprehensive topic overview

Introduction

Molluscum contagiosum is a contagious dermatological infection that predominantly a
poxvirus and presents as clusters of small umbilicated papules.
Molluscum infection is common. Exact estimates of overall prevalence vary, from 2-15% depending on the population
studied (particularly age, country and comorbidities).
2-3
It is most common in young children under the age of 10, decreasing in prevalence with increasing age. Molluscum is most
common in warm, tropical environments.

Aetiology

Molluscum is caused by cutaneous infection with molluscum contagiosum virus, a dsDNA poxvirus.
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It is transmitted through direct skin-to-skin contact, or indirectly via fomites. Transmission may also occur through
autoinoculation, as children scratch localised clusters of lesions and spread them further. Genital lesions may be spread
through sexual contact.

Risk factors

Key risk factors for contracting and transmitting molluscum infection include\:
Direct contact\: skin-to-skin contact with lesions.
Water-borne spread\: spread through shared bathwater or pool water, usually warm water.
Fomites\: sharing clothes or towels that may serve as fomites.
Environment\: transmission is more common in warm, tropical, humid environments.
Immunocompromise\: HIV infection or immunosuppressive medication increases the risk of infection with molluscum
and may also lead to lesions that are more persistent and recurrent, even in adults.
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Clinical features

History

Patients (or more likely, their parents) will report the appearance of lesions, usually within 2 weeks (but sometimes up to 6
months) of exposure. Siblings or close contacts may also be a
itchy but are not painful.
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Clinical examination

Molluscum lesions appear as small, round, pearly epidermal papules (raised bumps) with central umbilication. They are
generally 2-6mm in diameter but can be larger (giant mollusca). Lesions may become in
resolve. Molluscum may induce secondary local dermatitis, leading to surrounding erythema.
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They tend to appear in localised crops, particularly on the trunk, or in warm, moist places such as the axillae, groin, and
popliteal fossae. They may appear in rows if they are autoinoculated due to scratching, known as pseudo-koebnerisation.
Figure 1. Molluscum contagiosum on the thigh of a Caucasian child.
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Representative images in diverse skin types
Because of image reproduction rules, we are only able to directly include images with creative commons licencing.
Unfortunately, the majority of images of dermatological conditions available under this licence are in Caucasian
patients and fair skin tones.
We have included representative images here that we are not able to reproduce in this article directly, which we
encourage you to review.
Molluscum contagiosum lesions a
Molluscum contagiosum lesions a

Associated conditions

Molluscum dermatitis
A signi
in children who have pre-existing atopic dermatitis that is exacerbated by molluscum infection, rather than molluscum
causing dermatitis in children without a history of atopy.
Molluscum infections may be more common in children with dermatitis, due to disruptions in the integrity of the skin
barrier. 7
This dermatitis can be treated with emollients, and corticosteroids if needed.
Human immunode
Human immunode
molluscum. In patients with HIV, molluscum infection is typically more widespread, with larger and atypical lesions. Lesions
may be more persistent and may recur.
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Di

Figure 3. Viral warts.
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References

UptoDate. M o l l u s c u m c o n t a g i o s u m . 2020. Available from\: [LINK]
Koning et al. M o l l u s c u m c o n t a g i o s u m i n D u t c h g e n e r a l p r a c t i c e . 1994. Available from\: [LINK]
WHO. G u i d e l i n e s o n t h e T r e a t m e n t o f S k i n a n d O r a l H I V -A s s o c i a t e d C o n d i t i o n s i n C h i l d r e n a n d A d u l t s . 2014. Available from\:
[LINK]
Australasian College of Dermatologists. M o l l u s c u m c o n t a g i o s u m . 2015. Available from\: [LINK]
Wikimedia Commons. M o l l u s c u m c o n t a g i o s u m o n t h e t h i g h o f a C a u c a s i a n c h i l d . Licence\: [CC BY-SA]. Available from\:
[LINK]
DermNet NZ. M o l l u s c u m c r o p i n a l i n e a r p a t t e r n , p o s s i b l y d u e t o a u t o i n o c u l a t i o n d u e t o s c r a t c h i n g . ND]. Available from\: [LINK]
Licence\: [CC BY-NC-
DermNet NZ. C o m p l i c a t i o n s o f a t o p i c d e r m a t i t i s . 2004. Available from\: [LINK]
Wikimedia Commons. P l a n t a r w a r t s o n t h e s o l e o f a t o e . Licence\: [CC BY-SA]. Available from\: [LINK]
van der Wouden et al. I n t e r v e n t i o n s f o r C u t a n e o u s M o l l u s c u m C o n t a g i o s u m . eTG Complete. M o l l u s c u m c o n t a g i o s u m . 2020. Available from\: [LINK]
2017. Available from\: [LINK]

Reviewer

Consultant Dermatologist

Related notes

Acne vulgaris
Basal Cell Carcinoma (BCC)
Cellulitis
Cutaneous Squamous Cell Carcinoma (SCC)
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Erythema Multiforme

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Contents

Introduction
Aetiology
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