Doctor's Notes on Molluscum Contagiosum
Molluscum contagiosum is a common skin infection and primarily affects children and young adults. Signs and symptoms of this skin infection are raised, rounded, bumps on skin that are white, pink or flesh colored. The bumps can develop a dimple and contain a white, cheesy material. The disease in most people is benign and self-limited.
Molluscum contagiosum virus (MCV) is the cause the disease. There are at least four types of the MCV virus with MCV-1 being the most common cause. It is usually spread person-to-person but can be transmitted in contaminated clothing and other objects.
Molluscum Contagiosum Symptoms
The molluscum contagiosum rash begins as tiny painless papules (small raised bumps), each measuring about 2-5 mm in diameter.
- The lesions typically appear as dome-shaped papules that have a waxy, smooth, or pearly surface. They are either white, pink or flesh-colored, and with time, the center develops a dimple (umbilication), which can contain a white, cheesy substance. This core may be squeezed out easily. There may be redness and scaling at the edges of a lesion from inflammation or from scratching.
- Lesions may be located on almost any area of the skin. They are usually grouped in one or two areas, but they may be widely spread as well. In children, they commonly occur on the face, trunk, and limbs. Adults often get lesions on the genital area, the lower abdomen, the buttocks, and the inner thigh. Usually, fewer than 20 lesions appear, but several hundred are possible.
- The lesions do not affect the palms or soles and only rarely affect the mucous membranes of the mouth.
- Usually, there is no itching or tenderness, and there are no generalized symptoms such as fever, nausea, or weakness.
- People with weakened immune systems can develop widespread large lesions that can be persistent and rapidly spreading. These lesions often appear on the face, and they can come together (coalesce) to form giant lesions. Individuals with a weakened immune system include patients with AIDS, cancer, or those taking medications such as steroids or those undergoing cancer chemotherapy that cause impairment of the body's defense mechanisms.
- Though cases of severe molluscum contagiosum may indicate underlying infection with the HIV virus, the vast majority of people who develop molluscum contagiosum have no such serious underlying medical problem.
Molluscum Contagiosum Causes
Molluscum contagiosum is caused by the molluscum contagiosum virus (MCV), a member of the poxvirus family. Four types (I-IV) of molluscum contagiosum virus have been identified, with MCV-I being the most common cause of infection. Humans are the only known reservoir for this virus. The molluscum contagiosum virus occurs worldwide, but it is more common in developing countries, especially those in the tropics. It is estimated to account for 1% of all skin disorders diagnosed in the United States. Molluscum contagiosum infection is most common in children and young adults, with males being affected more commonly than females. It is most common in children 1 to 10 years of age. Individuals with weakened immune systems (immunocompromised), such as those with AIDS, also have a higher incidence of infection. Atopic dermatitis is also thought to be a risk factor for the development of molluscum contagiosum.
Eczema is a descriptive term for a chronic skin condition that usually begins in early childhood. It is seen most commonly in individuals who have family members who have asthma and hay fever. This is not to say that eczema is a classical allergic disease. There seems to be general agreement that this condition is inherited because of the complete loss or relative lack of a skin protein.
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Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.