Answer:
I would say it is a delusional disorder of somatic type
Step-by-step explanation:
Chronic delusional disorder has to do with paranoia and paraphrenia. Among the delusions that occur in this type of disorder there are several types: being persecuted (persecutory type), having a disease (somatic type), being loved by some person of greater importance (erotomaniac type), possessing an unfaithful partner (celotypic type) or have a prodigious gift (mega lomaniac type).
In somatic delusional disorder it is accompanied by hypochondriac delirium and is also known as monosymptomatic hypochondrial psychosis. It is a chronic pathology, it is characterized by a delirium that compromises the body or its functioning. In this case, think he has a disease and therefore constantly wash his hands.