What could be the cause of tiny pink bumps on the forearm?

Hello,

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I have seen your query and concern and examined your picture (attachment removed to protect the patient's identity). It seems you have developed Pityriasis rosea. Pityriasis rosea (PR) is a self-limiting eruption, which means it will subside on its own after a specified duration if not treated. The exact cause is unknown, though the following factors may be relevant:

Infection - A relationship with recent upper respiratory infections has been recorded and some studies have demonstrated the presence of HHV 7 (human herpes virus).

Drugs - Metronidazole, Gold, Isotretinoin, Captopril, Bismuth, Arsenic, Barbiturates, Clonidine, and Omeprazole have been reported to cause PR or PR-like rashes, often with atypical features and protracted course. Pityriasis rosea-like eruptions can also occur following hepatitis B and BCG vaccination (Bacillus Calmette-Guerin).

Other factors - Atopy, seborrheic dermatitis, and acne vulgaris are more common in patients with PR.

In classic Pityriasis rosea, the primary eruptions also called herald patch or mother patch, are seen in 50 % to 90 % of cases on their covered truncal area. You should understand that Pityriasis rosea is self-limiting, and has an innocuous and self-limiting nature. You can use topical corticosteroid Mometasone (Mometasone Furoate and Hexylene glycol) twice daily over the forearm for one week after consulting your general physician or nearby dermatologist. Hope this helps you.

Thank you.