Treating A Child With Multiple, Mildly Pruritic Papules
Patients with pruritus autoinoculate the virus through scratching and the spread of the virus among children is rapid and easy. Transmission reportedly occurs through direct skin contact and has occurred among: wrestlers and athletes in other sports with direct skin to skin contact; patients of infected surgeons; and children sharing baths, towels, gym equipment, clothes and other contaminated fomites. The average incubation time is between two and seven weeks.
The lesions in children arise mainly on the extremities and trunk area. In adults, the lesions tend be located on the lower abdominal wall, inner thighs and genitalia. Lesions are very rare on the palms and soles but I have seen two cases of giant molluscum (greater than 1 cm in diameter) on the plantar sole.
One would diagnose molluscum contagiosum via classical clinical findings. Clinicians should obtain a biopsy on lesions for a definitive diagnosis. The differential diagnosis includes verruca plana (flat warts), verruca vulgaris, keratoacanthosis, papular granuloma annulare, folliculitis, miliaria, varicella and lichen planus.
Molluscum contagiosum is far more common, dome-shaped and more papular than flat warts. They usually have an umbilicated or indented crater in the central portion of the dome. Verrucae vulgaris are usually drier, warty and are more vascular in nature. Keratoacanthoma are relatively uncommon on the lower legs and feet in younger patients, and are not as smooth and cone-shaped as molluscum contagiosum. Papular granuloma annulare is much more diffuse in nature and does not typically have a cratered dome.
Folliculitis is incorrect because these lesions involve hair follicles and appear much more inflammatory than molluscum lesions. Miliaria crystalline is a sweat retention reaction and is distinct in its clinical presentation. Varicella (chicken pox) may appear similar to molluscum lesions when it is in the crater phase but it is usually more diffuse and progresses to the ulcerative phase very quickly. The child is usually feverish and feels ill, which is uncommon with molluscum contagiosum. The lesions of lichen planus do not have the umbilicated appearance and they are usually easy to distinguish from molluscum contagiosum. One would diagnose lichen planus via biopsy and confirm it through the dermatopathology findings.
A Guide To Prevention And Treatment
Prevention of molluscum contagiosum includes good hygiene, bathing regularly and immediately after close physical contact sports, and avoiding direct contact with anyone who is already infected.
Treatment options for molluscum contagiosum include cryotherapy, curettage, topical acids (podophyllin, trichloroacetic acid, silver nitrate, salicylic acid, urea and lactic acid) or topical imiquimod 5% cream. Some systemic treatments using cimetidine have been recommended. However, in some cases, no treatment is necessary.
Cryotherapy is the preferred method of removing molluscum contagiosum lesion in most patients. I prefer the use of the CryoProbe® unit (CryoSurgical Technology) for these benign skin lesions once one has confirmed the diagnosis as this treatment is painless and effective for most patients. Depending upon the thickness of the lesion, two freeze cycles of 20 seconds are usually required. The lesions may blister slightly and then fall off in a few days to a week. If any lesions remain, one may repeat the process. Two treatment appointments are typically necessary. One may also use liquid nitrogen, either the spray or the dipstick method. However, this modality is much more painful. It is also common to see residual pigmentary changes following the removal of molluscum contagiosum with liquid nitrogen and the discoloration may remain for many months following treatment.