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Scabies

Scabies occurs in epidemics, in 30-year cycles with 15-year gaps between the cycles. The current epidemic we are in began in the mid-1960ís but unfortunately itís still going. About 2% of dermatologic visits are due to scabies, probably more than that because we probably miss it a lot. It is transmitted by close and casual skin to skin contact, but close contact. The more parasites the more chance of transmission. I think the key is, if several family members or members of a group, are itching, the likely diagnosis is scabies. Because thereís almost nothing else that will make a whole family itch. They arenít all taking the same medicine, usually, they arenít all allergic to the same clothes.

The itching is usually at night but a lot of things itch at night because you have your mind on other things during the day. Again, itís caused by hypersensitivity to the fecal matter and the saliva of the scabies, and it takes about four to six weeks to start itching because youíve got to get sensitized.

The characteristic locations, everybody is aware. The finger webs particularly, the sides of the finger, the wrists, the elbows, the axilla. The penis particularly. There is a dermatologist who I trained with who said, "If itís a man and itís not on the penis, itís not scabies." The female breast, the areolar area, the umbilicus and the lower buttocks. These are the characteristic locations we like to look at. You diagnose it by scraping it and demonstrating the mites.

Thereís a lot of special forms, and I wonít dwell on this too much. Iíll quickly go through these. Thereís so-called "Scabies in clean persons" which isnít a good term, but again you just arenít going to see many lesions, if somebody has very good cleanliness habits. Scabies incognito is steroid use. Somebody has scabies and you prescribe a steroid, it masks the signs and symptoms and also looks pretty unusual. Nodular scabies is what it says. You have big nodules because of a severe hypersensitivity reaction. Infants and young children; it looks different. It can be on the head. It usually isnít on the head of adults and vesicles are common in infants. Itís the only time you will see vesicles with scabies is with infants. Elderly people are difficult because they donít really show much reaction to the mite, but they itch like crazy, so they donít have all the papules and the burrows. They just itch like crazy, so itís diagnosed as senile pruritus or dry skin, when actually itís scabies. Of course Norwegian scabies is a severe form in mentally retarded patients and HIV disease.

Okay, just a few clinicals, and again, the finger webs are where we like to look for it and here are the characteristic lesions on the finger webs. Finger web again, characteristic papules. Sides of a finger, papules. This is so-called scabies in clean people. Thereís two bumps but itís still scabies, but itís a hard diagnosis.

This is an infant and these are blisters. The only time you see blisters with scabies is infants. This is interesting. This looks like a fungus infection. It looks like a dermatophyte. Itís a raised, heaped up scaly bordered lesion.

Treatment. Elimite, which is the pyrethrum 5% cream, single application. Works very well. Kwell isnít used as much as it used to be. For pregnant women and infants I use the sulfur, %6 in petrolatum applied nightly for three nights. Works very nicely. The newest thing, of course, is the ivermectin.

Alternative treatment for scabies, which is ivermectin and they just had a dosage guideline. Itís called Stromecti, itís the brand name for ivermectin. He says it simplifies the treatment of scabies with one oral dose.