Allergic Lymphangitis in Child: Case Report

Abstract

Objectives:

To report a case of allergic lymphangitis in a child, improving recognition and preventing mismanagement.

Introduction:

Allergic lymphangitis is a relatively rare disease. In children, the occurrence of allergic lymphangitis following mosquito bites has been relatively less frequently reported.

Methods:

We report a case of allergic lymphangitis in a child. A boy developed linear erythema on his arm following a mosquito bite, leading to the diagnosis of allergic lymphangitis. Antiallergic treatment was administered with favorable outcome.

Results:

Allergic lymphangitis is an allergic disorder that does not require antibiotic treatment.

Conclusion:

In the absence of infection markers, if the patient shows rapidly developing erythematous linear lesions after exposure to arthropods, allergic lymphangitis should be considered and empirical antibacterial treatment should be restricted.

Introduction

Allergic superficial lymphangitis caused by mosquito bites is an underestimated acute lymphangitis. So far, only a few cases have been reported. ¹ The pathogenesis of allergic lymphangitis remains unclear at present. It is generally considered to be the body’s allergic immune response to insect toxins,^2,3 and there are reports that it may be closely related to the increase in eosinophils and mast cell infiltration.^3,4 Ota ⁵ reported a case of allergic lymphadenitis in a 9-year-old boy in 2016, and there are other cases reported in adults.^6,7

Methods

Case Presentation

A 7-year-old boy presented with redness and swelling of his right upper limb, which had persisted for 1 day. Approximately 10 hours prior to presentation, the child experienced localized erythema and edema on his wrist and forearm following a mosquito bite. These symptoms were accompanied by pruritus. Subsequently, blisters developed on the wrist, surrounded by erythematous and edematous areas. The redness and swelling progressively spread in a linear pattern along the right arm toward the axilla, where notable erythema, edema, and tenderness were observed. The patient did not exhibit fever or any motor dysfunction in the affected limb. He was initially treated at a community health center with a single intravenous dose of cefixime. Despite observation for over 10 hours, there was no significant improvement in his condition, prompting referral to the emergency department.

The child had a history of developing papular lesions following mosquito bites; these typically measured approximately 1 cm × 1 cm, resolved spontaneously within several days, and were not associated with blister formation or linear erythema. Upon admission, physical examination revealed the following: temperature 37°C, pulse 92 beats/min, respiratory rate 22 breaths/min, and blood pressure 104/70 mmHg. Examination of the wrist demonstrated erythema and edema with 2 visible blisters. Linear erythema extended from the wrist to the axilla, where palpation revealed erythema, edema, tenderness, and several enlarged lymph nodes (the largest measuring approximately 1.5 cm × 1.5 cm). No enlarged lymph nodes were detected in the cervical or retroauricular regions (Figures 1 and 2).

Figure 1.

There are blisters at the mosquito—bitten area on the right forearm and the wrist.

Figure 2.

A strip—shaped red line can be seen from the wrist to the armpit.

The blood routine test revealed a white blood cell count of 9.8 × 10^9/L, with neutrophil percentage at 45.3%, absolute neutrophil value at 4.43 × 10^9/L, lymphocyte percentage at 42.3%, and absolute lymphocyte value at 4.14×10^9/L. The eosinophil percentage was 5.2% (normal range: 0.5-5.0%), and the absolute eosinophil value was 0.51×10^9/L (normal range: 0.02-0.5 × 10^9/L). C-reactive protein level was 5.4 mg/L, and procalcitonin was <0.05 ng/mL. Based on these findings, allergic lymphangitis following a mosquito bite was suspected. Initial treatment options included topical desonide cream or oral prednisone tablets. However, the child’s symptoms continued to progress, the pain was evident, and he did not comply with the topical medication or oral tablet treatment. Consequently, intravenous methylprednisolone at a dose of 1 mg/kg and oral cetirizine granules at a dose of 2.5 mg were administered. Four hours post-treatment, the redness and swelling in the child’s arm diminished, axillary pain resolved, and mild itching persisted (Figures 3-5). On the second day, intravenous methylprednisolone and oral cetirizine granules were continued. By the third day, methylprednisolone was discontinued, and only cetirizine granules were administered orally. Three days later, there was no residual redness or swelling in the child’s arm, and the wrist blisters had subsided.

Figure 3.

The redness and swelling of the arm have alleviated.

Figure 4.

The red line on the arm has disappeared.

Figure 5.

The redness and swelling of the entire arm subsided, and the redness and swelling in the armpit were significantly alleviated.

Discussion

Acute lymphangitis is an inflammation of the superficial lymphatic vessels, characterized by linear erythema extending to the proximal regional lymph nodes, and is usually considered to be related to acute bacterial infections, such as Staphylococcus aureus, Streptococcus pyogenes, etc. Therefore, in clinical practice, doctors usually administer systemic antibiotic treatment to patients. However, acute lymphangitis can also be caused by various other non - bacterial etiologies, such as viral or fungal infections, arthropod bites, etc. ² Lymphangitis caused by arthropods, especially mosquito bites, is mostly related to allergic reactions,^{2 -4} which we call allergic lymphangitis.

Allergic lymphangitis is an immediate—type allergic reaction that occurs after insect bites. ² Marque et al ⁴ analyzed 6 cases of secondary superficial lymphangitis following arthropod bites, indicating that it is a benign disease similar to common bacterial lymphangitis, with no evidence of bacterial infection. Instead, the presence of eosinophils and mastocytes in the inflammatory infiltrate was found, further indicating an immunological–allergic process. The clinical manifestations of allergic lymphangitis are that there is generally no pain at the bite site but itching. Patients usually have no fever and may be accompanied by lymph node enlargement. In this case, the child had a normal body temperature, obvious itching at the affected area, but tenderness in the axillary lymph nodes. Auxiliary examinations showed that white blood cells, C-reactive protein, and procalcitonin were normal, suggesting that it was not caused by bacterial infection, while the increase in eosinophils suggested the presence of an allergic reaction in the body, which was consistent with previous reports.^3,4 If allergic lymphangitis is considered, the use of antibiotics should be avoided. Because similar cases are relatively rare in clinical practice, leading to insufficient understanding among clinicians and the overuse of antibiotics. Clinicians should be aware of allergic lymphangitis that occurs after arthropod bites, especially when children have no fever and are accompanied by lymph node enlargement, which may be an allergy, and should be treated with glucocorticoids and anti-histamines instead of antibiotics.^{3 -6}

For mild cases, topical corticosteroids combined with oral antihistamines are generally sufficient. Moderate-to-severe presentations (eg, extensive lymphangitis or severe pain) may require oral corticosteroids. When oral administration is ineffective or impractical, a short course of intravenous corticosteroids may be considered, with subsequent transition to oral therapy upon clinical improvement. In this case, the boy had severe pain and was unable to combine local application of hormones or oral prednisone tablets. Therefore, intravenous methylprednisolone treatment was chosen. After the symptoms were alleviated, the treatment was stopped and only oral antihistamines were taken. Although intravenous hormones were effective in this case, their potential side effects (such as the risk of infection and elevated blood sugar) need to be carefully weighed based on the specific conditions of the patient.

Conclusion

In the absence of infection markers, if the patient shows rapidly developing erythematous linear lesions after exposure to arthropods, allergic lymphangitis should be considered and empirical antibacterial treatment should be restricted.