Clinically, the chronic meth user may present with formication (speed bumps, meth sores, etc.) which are unusual lesions and scabbing on the face, arms, torso and legs (Figures 1, 2 and 3). These cutaneous manifestations are commonly caused by the user scratching at the imaginary insects (“crank bugs, meth mites, etc.) that the user feels crawling beneath the skin. These lesions frequently become infected from scratching, unsanitary conditions and vasoconstriction of the tissue. The name ‘formication’ comes from the fact that ants inject formic acid when they bite. Some research has indicated that there may be a chemical or allergic skin reaction to the drug that causes this sensation.49 The feeling of this sensation is called delusional parasitosis, and with meth use it is hypothesized to be the result of vasoconstriction of the nerve endings on the skin and cause the addict feelings of something irritating or “crawling” under the skin.69
When a meth user is under the influence of the drug, they have decreased appetite and increased activity. Consequently, the long-term user will often have a marked weight loss and may show effects of malnutrition. Additional physical indicators of meth use include hyperthermia, diaphoresis, hypertension, tremors, paranoia, hyperactivity, nausea, vomiting, diarrhea, unusual body odors, dilated pupils, blurred vision, unexplained bruises from falling, persistent cough, severe lung and kidney damage, inflamed or eroded nasal septum and track marks at injection sites. Hyperthermia and convulsions occur with methamphetamine overdoses, and if not treated immediately can result in death.21
The oral manifestations will be discussed later. Figures 4 and 5 demonstrate some of the physical effects of methamphetamine use.