Lithium is a mood-stabilizing medication used to manage bipolar disorder. Despite its therapeutic benefits, lithium is known to cause various side effects, including common dermatological reactions. An acne-like eruption is frequently reported, potentially affecting up to one-third of individuals taking the medication. Understanding the underlying biological mechanisms helps in managing this distressing side effect while continuing treatment.
Cellular Mechanisms: How Lithium Affects Skin Glands
The link between lithium and acne stems from the drug’s interference with several cellular signaling pathways within the skin. Lithium acts on enzymes that regulate cell growth and inflammation, processes directly involved in acne lesion formation. A primary mechanism involves the inhibition of the enzyme Glycogen Synthase Kinase 3 (GSK-3), a major regulator of cell function.
In normal skin, GSK-3 helps control the proliferation and differentiation of keratinocytes, the cells that make up the outer layer of the skin. By inhibiting GSK-3, lithium promotes the increased proliferation of these keratinocytes. This rapid and uncontrolled growth leads to hyperkeratinization, the clogging of the hair follicle.
This cellular disruption also triggers an inflammatory response that is distinctly different from typical adolescent acne. Lithium causes an increase in inflammatory chemicals called cytokines, which heighten the skin’s overall reactivity. The medication is also thought to increase the activity of immune cells called neutrophils, drawing them to the skin where they contribute to inflammation and the formation of red, raised lesions.
The drug also appears to disrupt the normal function of the sebaceous glands, which produce sebum, or skin oil. Lithium has been shown to disrupt sebum production, leading to an excess of oil that further contributes to the clogging of pores. This combination of increased sebum, hyperkeratinization, and heightened inflammation creates the environment for a persistent acneiform eruption.
Distinguishing Lithium-Induced Skin Reactions
The skin reaction caused by lithium is often classified as an acneiform eruption rather than classic Acne vulgaris. Classic acne typically presents with a mix of blackheads (comedones), whiteheads, and deeper cysts. In contrast, lithium-induced lesions are often monomorphic, presenting primarily as small, red bumps or pustules without the typical comedones.
A notable difference is the location of the breakouts, as lithium-related eruptions frequently appear on the trunk, arms, and legs, rather than being confined to the face and hairline. This distribution is unusual for standard acne, making it a distinguishing feature. Lithium can also manifest as chronic folliculitis, an inflammation around the hair follicle, sometimes resembling keratosis pilaris.
Lithium can also exacerbate a pre-existing case of Acne vulgaris, making it more severe or resistant to prior treatments. Because lithium can cause or worsen several distinct skin conditions, including psoriasis, an accurate diagnosis by a dermatologist is necessary to distinguish the specific type of eruption for effective management.
Treatment Approaches for Continued Medication Use
For individuals experiencing a skin reaction, they must consult their prescribing physician before discontinuing lithium therapy. Abrupt cessation can lead to a dangerous relapse, as the medication is prescribed for serious psychiatric conditions. Management focuses on dermatological treatments that are safe to use alongside the mood stabilizer.
Topical treatments are the first line of defense and include standard acne medications like benzoyl peroxide, which reduces surface bacteria and inflammation. Dermatologists may also prescribe topical retinoids, which help normalize the skin cell turnover process and unclog follicles by combating the hyperkeratinization effect. Patients using retinoids should be cautious about sun exposure, as these medications can increase skin sensitivity to ultraviolet light.
In more severe cases, oral antibiotics may be used to reduce inflammation and bacterial presence, but this requires careful monitoring. Certain antibiotics used for acne, such as those in the tetracycline class, can interact with lithium and potentially increase the risk of lithium toxicity. Isotretinoin is occasionally considered for the most severe, unresponsive cases, but its use alongside lithium carries a heightened risk due to its association with central nervous system side effects like psychosis and depression.
A psychiatrist may also work with the patient to determine if adjusting the lithium dosage or closely monitoring the serum concentration can help mitigate the dermatological side effects. Sometimes, a small reduction in the therapeutic dose is enough to clear the skin while maintaining the medication’s mood-stabilizing benefits.