42 years-old male, ex-IDU, addicted to the abuse of several substances with a predominance of cocaine over heroin. Smoker of around 20 cig. Per day. Sporadic use of THC and alcohol. HCV-positive. No previous history of diabetes mellitus, dyslipidaemia or other relevant conditions.

Upon imprisonment, apart from a mixed abstinence syndrome, the patient presents rounded lesions in his arms, nummular (of the size of a one cent of a euro coin) in different stages: some ulcerated, others as scabs and others as scars (see Pictures). Absence of general symptoms.

The patient reports that frequently, in association with the use of drugs, he has the sensation of small insects crawling under the skin of his arms. When he tries to scratch them off he causes the lesions. He is unclear or whether this takes place after the use of drugs or during the periods of abstinence.

The blood tests only reveal a slight hypertransaminasemia. The “prickling” or “formication” is a particular tactile hallucination where the patient has the sensation of something crawling under his/her skin. Sometimes it is a delirious interpretation of a sensation attributed to insects or worms. Prickling can occur in delirium due to alcohol abstinence and following the intoxication by cocaine or due to its intoxication itself, if severe¹.

The delirious infestation, or syndrome or Morgellons^{2 3}, consists of a delirium where the patient believe that he is infected by infectious agents such as insects or parasites and it is not associated to drug abuse.

Our patient, with the abstinence to drugs and the prescription of low-doses of neuroleptics stopped causing himself new lesions although the scars remain.

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