That Skin Rash.


What is that? a mollusk? noooo…its a rash. Wait what?

Molluscum Contagiosum is a benign superficial skin disease caused by the Molluscum contagiosum virus, which is a large double stranded DNA virus in the poxvirus family. The poxvirus replicates in the cytoplasm of host keratinocytes producing discrete, small (2-5mm), pearly flesh colored or pink dome shaped papules with a central umbilication or depression. The core of these lesions can occasionally be expressed and consists of a white cheesy material. The lesions are generally painless, but may become inflamed, red, scaly and swollen secondary to scratching or a hypersensitivity reaction. They most commonly occur in the intertriginous regions such as the axillae, groin and neck. They rarely occur on the face or periocular region, but can occur anywhere on the body except the palms and soles. In adults, they are most common in the pubic and genital areas, whereas genital manifestations in children could be an indication of abuse.

The infection is found worldwide, but is more common in developing countries. It has also mainly been considered a pediatric disease, typically occurring in toddlers or younger children over 1 year of age.

The virus is spread by direct contact with an infected individual or by contact with infected fomites, but the virus does not develop latency like the herpes virus. It is unclear as to whether the disease may be spread by simple contact with intact lesions or if breaking the lesion and the subsequent transfer of the lesion’s core material is necessary for transmission. Secondary spread of lesions may occur by autoinoculation by excoriation (especially in patients with atopic dermatitis) as well as by shaving and electrolysis. Swimming pools, steam baths, saunas, and communal spray baths have also been considered as modes of transmission likely because the warm and wet environment facilitates the spread of the virus by fomites. Vaccination against smallpox in infancy had not been found to be protective. The virus is completely contained in this protective sac allowing it to avoid triggering the host immune response. The incubation period of the virus has been estimated to be between 2 weeks and 6 months, with the lesions usually resolving spontaneously in 6-12 months; however some can take up to 4 years to resolve. Atopic dermatitis may be a risk factor for contracting the molluscum contagiosum virus due to barrier breaks and immune cell dysfunction in atopic skin. Patients with atopic dermatitis are also more likely to autoinoculate because of the underlying pruritis from their atopic dermatitis. Immunocompromised patients often have larger (over 15 mm) and more widespread lesions that could be disfiguring and are more resistant to standard therapy.

Diagnosis is generally made merely by appearance of the lesions. Skin biopsy may be necessary in immunocompromised individuals to rule out malignancy or fungal infections. Skin biopsy will reveal “molluscum bodies” which are large, eosinophilic, round, intracytoplasmic inclusions in the epidermis. A microscopic evaluation of a potassium chloride preparation of the soft material obtained from the umbilicated part …