Unmasking Long COVID: Healing Through Immune Modulation in Adolescents

Sarah Cassidy, ND

Abstract

Long COVID, or post-acute sequelae of SARS-CoV-2 infection, is an increasingly recognized condition affecting not only adults but also adolescents. Though often underdiagnosed in younger populations, it can present with a wide range of symptoms involving multiple systems, including fatigue, cognitive dysfunction, autonomic irregularities, and dermatologic or allergic-type reactions.⁵ Awareness of these presentations in adolescents remains limited.

A 16‑year‑old female presented to the clinic with a constellation of symptoms, including fatigue, eyelid redness, dryness, swelling, and severe itching. She also reported brain fog and palpitations. Most of her symptoms began approximately two months ago following a mild cold‑like illness and a positive COVID‑19 test. She had not felt normal since. Comprehensive blood work was performed, but all results were within normal limits.

Given the persistence and multi‑system nature of her symptoms, a post‑COVID‑19 condition (Long COVID) was considered. Management included herbal and vitamin supplementation, and over a two‑month period, the patient’s symptoms fully resolved.

This case exemplifies a potential Long COVID presentation in an adolescent, with notable dermatologic, cognitive, and cardiac symptoms that responded well to supportive care.

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Background

Long COVID can induce widespread inflammation across multiple organ systems, including the heart, lungs, kidneys, brain, skin, eyes, and gastrointestinal tract, affecting both pediatric and adult populations.⁴ In children, the condition is often diagnosed as Multisystem Inflammatory Syndrome in Children (MIS-C), while in adults, it is referred to as MIS-A.⁶ Although children typically recover more quickly than adults, it is concerning that many pediatric cases of MIS-C occur in individuals who experienced mild or no symptoms during the initial COVID-19 infection and had no prior underlying health conditions.⁶

Symptoms of Long COVID in children may manifest intermittently, reemerge over time, and persist for extended periods—ranging from months to years.⁵ These can include fatigue, cognitive dysfunction (brain fog), dermatological inflammation, autonomic dysfunction (e.g., palpitations), anosmia, mood changes, and gastrointestinal or musculoskeletal symptoms.⁵

As of current estimates, over 680 million individuals globally have contracted COVID-19, with research suggesting that 10–20% may go on to develop Long COVID.⁴ This case highlights the importance of early identification and holistic management of symptoms in younger patients to prevent chronic dysfunction.

Case Presentation

Patient Profile:
16-year-old high school student—active, otherwise healthy, no medications or supplements. No dietary restrictions, maintains a nutritious diet, abstains from alcohol and smoking.

Chief Complaints:
Eyelid swelling, redness, and itching; fatigue; brain fog; palpitations.

Subjective:
The patient reported progressive eyelid redness, dryness, and swelling starting two months ago. The rash initially began as a small dry patch and later expanded to both eyelids. She described the skin as extremely itchy and inflamed, impacting her self-image. Topical creams provided no relief.

She also experienced persistent fatigue, uncharacteristic of her active lifestyle, and reported occasional word-finding difficulty and cognitive slowing. Palpitations occurred randomly, lasting approximately five minutes, with no chest pain or shortness of breath.

She recalled having mild cold-like symptoms and testing positive for COVID-19 about two months earlier. She denied recent travel, vaccinations, or other known exposures.

Objective:
The patient appeared well-nourished, in no acute distress. Ocular exam revealed mild bilateral eyelid swelling (+1) with erythema and dry, flaky periorbital skin. Visual acuity was 20/20 bilaterally; normal visual fields, EOMI, and fundoscopic exam.

The remainder of the physical exam was unremarkable. ENT, cardiac, pulmonary, GI, MSK, neuro, and psych evaluations were within normal limits.

Labs & Imaging:

• Elevated ESR, indicating mild systemic inflammation
• Low Vitamin D (22 ng/mL)
• CBC, CMP, A1C, B12, ANA, hs-CRP, Lyme WB, mold panel – all normal
• Cardiac Workup: ECG and echocardiogram unremarkable – no myocarditis, arrhythmia, or structural heart disease identified

Assessment

This adolescent presented with a constellation of multi-system symptoms—ocular inflammation, fatigue, cognitive dysfunction, and palpitations—following a mild COVID-19 infection. Despite normal standard labs and cardiology workup, her symptom duration, severity, and timing suggest a case of Long COVID, consistent with recent literature on pediatric post-viral syndromes.⁵^,⁶

Notably, her symptoms also resembled MIS-C in a milder, chronic form—without overt systemic organ failure, but with ongoing immune dysregulation. The mild elevation in ESR and low vitamin D levels further support an underlying inflammatory process, as echoed in studies linking vitamin D deficiency with Long COVID symptoms.¹

Interventions/Plan

Supplementation Protocol (2 months):

• Vitamin C: 1000 mg, TID
• Zinc: 30 mg daily
• Probiotic Complex (100B CFU)
• NAC: 600 mg daily
• Vitamin B12: 1000 µg daily
• Vitamin D₃: 10,000 IU daily
• Oregano Oil: 1 capsule daily
• Spirulina: 3g daily
• Quercetin: 250 mg BID

Anti-Inflammatory Diet:
Avoid: Dairy, sugar, processed foods, seed oils, red meat, gluten, nightshades
Include: Organic lean proteins, fruits, vegetables, coconut/olive oil, turmeric, garlic, non-dairy milk/yogurt, seeds, nuts, ginger

Outcome

At the two-month follow-up, the patient showed complete resolution of symptoms:

• Dermatologic: Eyelid inflammation cleared, skin returned to normal
• Cognitive: Brain fog and word-finding difficulties resolved
• Fatigue: Marked energy improvement; resumed full academic and physical activities
• Cardiac: Palpitations became rare and non-disruptive

This clinical improvement correlated with strict adherence to the supplement regimen and dietary plan.

Discussion

This case illustrates the nuanced and under-recognized presentation of Long COVID in adolescents. Although much attention has been given to adult manifestations, pediatric populations can also experience significant post-viral sequelae, even after asymptomatic or mild acute illness.⁵

The eye involvement in this case—specifically eyelid inflammation and dermatitis—is notable and likely represents an inflammatory dermatologic response, possibly exacerbated by immune dysregulation post-infection. This is supported by the growing body of evidence that SARS-CoV-2 may disrupt epithelial barriers and promote persistent immune activation, including in ocular tissues.³^,⁴

Cognitive symptoms such as brain fog and fatigue are consistent with neurological effects of post-viral inflammation and oxidative stress.⁴ Palpitations suggest autonomic nervous system involvement, a common finding in both pediatric and adult Long COVID cases.⁵

The rationale for using a naturopathic treatment approach was based on the goals of:

• Reducing systemic inflammation
• Supporting immune function
• Enhancing antioxidant capacity
• Replenishing key micronutrient deficiencies

Evidence supports the role of vitamin D, zinc, NAC, quercetin, and probiotics in modulating inflammatory and immune pathways relevant to Long COVID.¹^,² Spirulina and oregano oil add additional immune-modulating and antimicrobial benefits, while an anti-inflammatory diet helps reduce pro-inflammatory dietary triggers, further enhancing recovery.²

This integrative approach was not only well-tolerated but led to complete symptom resolution within two months, suggesting a promising adjunctive path for similar presentations in adolescents.

Conclusion

This case demonstrates how multi-system Long COVID in adolescents can mimic inflammatory syndromes like MIS-C, even without severe acute illness. It also highlights the therapeutic potential of naturopathic strategies, including diet and targeted supplementation, in restoring immune balance and resolving persistent symptoms. Early recognition and integrative intervention may offer a path toward full recovery in affected adolescents.

References

1.  Di Filippo L, Frara S, Nannipieri F, et al. Low vitamin D levels are associated with Long COVID syndrome in COVID-19 survivors. J Clin Endocrinol Metab. 2023;108(10):e1106-e1116. doi:10.1210/clinem/dgad207
2. Booker A, Zabetakis I, Teusch NE, Dalby A, Hartung T, Peter AE. Editorial: Multisystem inflammatory syndrome observed post-COVID-19: the role of natural products, medicinal plants and nutrients and the use of prediction tools supporting traditional forms of diagnosis. Front Pharmacol. 2025;16:1539793. doi:10.3389/fphar.2025.1539793
3. Huang C, Huang L, Wang Y, et al. 6-month consequences of COVID-19 in patients discharged from hospital: a cohort study. Lancet. 2021;397(10270):220-232. doi:10.1016/S0140-6736(20)32656-8
4. Raveendran AV, Jayadevan R, Sashidharan S. Long COVID: an overview. Diabetes Metab Syndr. 2021;15(3):869-875. doi:10.1016/j.dsx.2021.04.007
5. Zhu Y, Li X, Wang J, et al. Long COVID and its impact on children and adolescents: a systematic review. Front Pediatr. 2023;11:1045827. doi:10.3389/fped.2023.1045827
6. National Institute of Allergy and Infectious Diseases. (2023, August). Long COVID and multisystem inflammatory syndrome in children (MIS-C). U.S. Department of Health and Human Services. Retrieved August 1, 2025, from https://www.niaid.nih.gov/diseases-conditions/long-covid-multisystem-inflammatory-syndrome-children-misc