molluscum contagiosum

23 Jul

Molluscum contagiosum is a viral skin infection that is caused by molluscipoxvirus. It mainly affects children but it can affect adults too. Its appearance includes bumps that are raised, small and firm. It can commonly be found on the face, neck, arm, hands and genital area. In most cases, it is a self resolving condition which improves within 6-12 months.

- In children, the annual incidence of molluscum contagiosum ranges from 2-10% [1]
- A large UK survey found that the average yearly incidence is 261 per 100,000 and over 80% of reported cases occurring in children under 15 years [2]
- Sexual transmission affected young adults the most
- The prevalence of the disease in HIV patients ranged from 5-33% [3]
- Direct contact from skin-to-skin
- Contact with infected objects such as towels, bedding, furniture
- Sexual contact with infected people
- Bathing or swimming together as wet conditions are likely to spread the disease [4]
Medical Students
- The molluscum contagiosum virus (MCV) infects only the epidermis and replicates within the cytoplasm of epithelial cells.
- Transmission occurs through direct contact with infected skin or fomites; the exact degree of skin trauma needed for entry is unknown.
- The incubation period is typically 2–7 weeks, with the primary infection starting in the basal epidermal layer.
- Viral replication and cell proliferation cause lobulated epidermal growths, forming molluscum bodies at the lesion’s center.
- The virus can evade immune detection via virus-specific proteins and does not establish latency.
- Cell-mediated immunity is crucial for lesion clearance; humoral immunity plays a minor role.
- Inflammation may occur, especially in immunocompromised individuals (e.g., HIV).
Patients
- The virus only affects the outer layer of your skin and grows inside skin cells.
- It spreads through skin contact or by touching shared items like towels or toys.
- After being exposed, it usually takes 2 to 7 weeks before any spots or bumps appear.
- The virus causes small growths on the skin, with a white or waxy center filled with viral material.
- People with weaker immune systems, like those with HIV, may get more severe or longer-lasting spots.
- The virus can hide from your immune system, which is why it might stick around for a while.
- Your body uses specific immune cells to fight off the virus — but the usual infection-fighting antibodies don’t play a big part.
- Because the virus doesn’t cause a strong immune memory, it’s easy to get re-infected.
- Exposure to an infected person/object or sharing a personal item with someone who has infected
- Children with eczema
- Athletes in contact with others or share equipment
- Conditions that are warm, humid and crowded
- Patients with weakened immune systems [6]
- Clusters of pink, dome shaped papules (spot)
- Smooth, waxy or pearly spots
- Found on the face, trunk (torso), hands, feet and genitalia regions
- Inflammation
- Itchiness
- Painless [7]
- Clinical exam of the skin based on appearance
- May require a skin scraping to examine under the microscope to rule out infection or diagnose the condition [6]
- Herpes simplex virus
- Flat warts
- Chickenpox
- Nevi (moles)
- Milia- white spots
- Lichen planus- purple, flat topped bumps
- Follulitis- inflammation of the follicle seen with red bumps
- Acne vulgaris
- Tumours eg. basal cell carcinoma
- Fungal infections of the skin
- Keratoacanthoma- type of skin tumour that looks similar to the non-melanoma condition, squamous cell carcinoma [8,9]
Medical Student
- Reassure: Benign, self-limiting condition in immunocompetent individuals.
- Spontaneous resolution usually within 18 months.
- Treatment is often not required, but options include:
  - Imiquimod cream
  - Podophyllotoxin
  - Cryotherapy
  - Note: Limited evidence for high efficacy of any single treatment.
- Prevent spread by avoiding:
  - Sharing towels, clothes, bedding.
  - Scratching or squeezing lesions.
- School/gym/swimming exclusion not necessary, but cover lesions with waterproof dressings for swimming.
- Treat any secondary infection, discomfort, or complications.
- Refer to dermatology or specialist if lesions are extensive, persistent, or problematic.
- Same general advice: self-limiting, treatment rarely required.
- Physical/topical treatments may be used, but evidence is weak.
- Prevent spread:
  - No sharing personal items.
  - Avoid shaving/waxing the genital area.
  - Use condoms, though protection is only partial.
- STI and HIV screening recommended in adults.
- Safeguarding: In children, refer for suspected sexual abuse only if there are additional concerns or evidence.
Patient
- Molluscum contagiosum is a mild skin infection that usually goes away on its own.
- Most healthy people get better within 18 months without needing treatment.
- Some creams (like imiquimod or podophyllotoxin) or freezing (cryotherapy) may be used, but none work for everyone.
- Don’t share towels, clothes, or bedding.
- Try not to scratch or pick at the spots.
- You don’t need to stay away from school, the gym, or swimming — but cover the spots with a waterproof plaster if swimming.
- If the spots are sore or infected, see your doctor.
- You may be referred to a specialist if they don’t go away or become uncomfortable.
- It can still clear on its own, but the same treatments may be used if needed.
- Don’t shave or wax the area to avoid spreading it.
- Condoms are a good idea but don’t fully protect against spreading it.
- Adults may need a check-up for other STIs including HIV.
- In children, a referral for abuse is only made if there are other signs or concerns.
- Mental health problems and distress caused by appearance
- Itchiness (pruritis) and redness (erythema)
- Scarring
- Secondary bacterial infection
- Conjunctitivits
- Molluscum dermatitis- eczema surrounding the site of infection [9]
- Molluscum contagiosum is limited to undeveloped countries
- The condition is asymptomatic
- In all cases, the condition is self resolving so no treatment is required [11]
- Which conditions pose as a risk of spreading the condition?
- How do I know if my symptoms are getting worse?
- How long does treatment take before being effective?
- Who do I approach if I start showing signs of the complications of the condition?
- How is the condition prevented?
- American Academy of Dermatology
- British Association of Dermatologists
- NHS
[1] PubMed: Molluscum Contagiosum Epidemiology and Management in Children
[2] NCBI (PMC): Molluscum Contagiosum: Review of Clinical Features and Management
[3] Patient.info: Molluscum Contagiosum Diagnosis and Management
[4] DermNet NZ: Molluscum Contagiosum Clinical Overview and Images
[5] Medscape: Molluscum Contagiosum Clinical Overview
[6] American Academy of Dermatology: Who Gets Molluscum Contagiosum and Why
[7] MSD Manual (Professional): Molluscum Contagiosum Viral Skin Disease
[8] VisualDx: Molluscum Contagiosum
[9] NICE CKS: Molluscum Contagiosum Differential Diagnosis
[10] NICE CKS: Molluscum Contagiosum Management Guidelines
[11] Practical Dermatology: Molluscum Contagiosum Tips for Clinical Practice