Differential Diagnosis for Anal Pruritus in a 7-year-old Boy
- Single most likely diagnosis
- Enterobiasis (pinworm infection): This is the most likely diagnosis given the patient's symptoms of anal pruritus, especially at night, and the recent history of camping and swimming in a lake. Pinworms are highly contagious and can be spread through contaminated water or close contact with an infected person.
- Other Likely diagnoses
- Eczema or atopic dermatitis: The patient's symptoms of perianal erythema and excoriations could be consistent with eczema or atopic dermatitis, especially if the patient has a history of allergies or skin conditions.
- Fungal or bacterial infections: The patient's symptoms of perianal erythema and excoriations could also be consistent with a fungal or bacterial infection, such as candidiasis or streptococcal dermatitis.
- Allergic reaction: The patient's symptoms could be an allergic reaction to something he came into contact with during the camping trip, such as insect bites, plants, or soap.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Inflammatory bowel disease (IBD): Although less likely, IBD (such as Crohn's disease or ulcerative colitis) can cause anal pruritus and perianal disease, and is important to consider due to its potential for serious complications if left untreated.
- Sexual abuse: Unfortunately, anal pruritus can also be a symptom of sexual abuse, and it is essential to consider this possibility, especially if the patient's symptoms are severe or persistent.
- Rare diagnoses
- Lichen sclerosus: A rare skin condition that can cause anal pruritus and perianal disease.
- Psoriasis: A chronic skin condition that can cause anal pruritus and perianal disease, although it is less common in children.
- Threadworms or other parasitic infections: Other parasitic infections, such as threadworms, can cause anal pruritus, although they are less common than pinworms.