Localized pigmentation disorder after subcutaneous pegylated interferon beta-1a injection

Area of Science:

• Dermatology
• Pharmacology

Background:

• Interferon beta-1a is a biologic therapy used for autoimmune diseases.
• Subcutaneous administration is a common route for interferon beta-1a.
• Adverse skin reactions to interferons are known, but localized pigmentation disorders are rare.

Observation:

• A 42-year-old female developed unusual skin lesions after receiving subcutaneous polyethylene glycol (PEG) interferon beta-1a.
• Dermatological examination revealed hypochromic macules coalescing into a large patch and greyish hyperpigmentation at abdominal injection sites.
• Lesions worsened over a 6-month period, and other conditions like fungal infection, vitiligo, and pityriasis alba were ruled out.

Findings:

• This case represents the first report of a localized pigmentation disorder associated with interferon beta therapy.
• The observed skin lesions, characterized by hypochromic macules and annular hyperpigmentation, are distinct from typical vitiligo or other known interferon-induced hyperpigmentation.
• The clinical presentation suggests a unique reaction to subcutaneous PEG interferon beta-1a.

Implications:

• This case highlights a novel cutaneous adverse effect of PEG interferon beta-1a, necessitating increased clinical awareness.
• Understanding the mechanisms behind this localized pigmentation disorder may offer insights into interferon-induced dermatological reactions.
• Further research is warranted to elucidate the pathophysiology and potential management strategies for this rare side effect.