This case was reported in a literature article and described the occurrence of Wells syndrome in a child male patient who received HAB (Hepatitis A and Hepatitis B vaccine) for prophylaxis. Co-suspect products included HAB (Hepatitis A and Hepatitis B vaccine) for prophylaxis, DTPa-IPV for prophylaxis and MMRV for prophylaxis. On an unknown date, the patient received Hepatitis A and Hepatitis B vaccine at an unknown dose, Hepatitis A and Hepatitis B vaccine at an unknown dose, DTPa-IPV at an unknown dose and MMRV at an unknown dose. On an unknown date, unknown after receiving Hepatitis A and Hepatitis B vaccine, not applicable after receiving Hepatitis A and Hepatitis B vaccine and DTPa-IPV and an unknown time after receiving MMRV, the patient experienced Wells syndrome, vesicular rash, erythema, skin ulcer, edema, pruritus, Wells syndrome, vesicular rash, erythema, skin ulcer, edema, pruritus, Wells syndrome, vesicular rash, erythema, skin ulcer, edema and pruritus. Rechallenge with Hepatitis A and Hepatitis B vaccine was positive. On an unknown date, the outcome of the Wells syndrome, vesicular rash, erythema, skin ulcer, edema, pruritus, Wells syndrome, vesicular rash, erythema, skin ulcer, edema and pruritus were recovered/resolved and the outcome of the Wells syndrome, vesicular rash, erythema, skin ulcer, edema and pruritus were unknown. The reporter considered the Wells syndrome, vesicular rash, erythema, skin ulcer, edema and pruritus to be related to Hepatitis A and Hepatitis B vaccine. The reporter considered the Wells syndrome, vesicular rash, erythema, skin ulcer, edema and pruritus to be related to Hepatitis A and Hepatitis B vaccine. The reporter considered the Wells syndrome, vesicular rash, erythema, skin ulcer, edema and pruritus to be related to DTPa-IPV. Additional information was provided. This case was reported in a literature article and described the occurrence of paediatric Wells Syndrome in a male patient aged less than 4-years who was vaccinated with unspecified hepatitis A/B vaccine (manufacturer unknown) for prophylaxis. The patient was otherwise well. No information on medical or family history or concurrent condition or concomitant medication was provided. On an unspecified date, the patient received unspecified hepatitis A/B vaccine (administration route and site unspecified; dosages unknown; batch number not provided). Age of vaccination was not provided. On an unspecified date, shortly after vaccination, the patient experienced erythematous vesicular plaques, ulceration, oedema, and pruritus on the left foot and ankle. On an unspecified date, the patient again received hepatitis A/B vaccine (administration route and site unspecified; dosages unknown; batch number not provided). Shortly after vaccination, the patient again experienced erythematous vesicular plaques, ulceration, oedema, and pruritus on the left foot and ankle. On an unspecified date at the age of 4-years, the patient received Tdap-IPV and MMRV vaccines (administration route and site unspecified; dosages unknown; batch number not provided for both). 10 days after vaccinations, the patient presented with erythematous vesicular plaques, ulceration, oedema, and pruritus on the left foot and ankle. Biopsy results showed eosinophilic infiltrates and flame figures suggestive of Wells syndrome. Patch testing was performed to neomycin, polymyxin B, formaldehyde, phenoxyethanol, glutaraldehyde, aluminum hydroxide, and polysorbate 20 (Tween 80). A 1+ reaction was observed to neomycin and aluminum hydroxide, along with a recall reaction of Wells syndrome of the feet bilaterally. Treatment was unknown. The outcome of the event was not reported. The author commented, Ours is the first known case of paediatric Wells Syndrome triggered by non-thimerosal vaccine components confirmed by patch testing'. The author stated, our case supports the hypothesis of CD4+ T-cell involvement, with the occurrence of a recall reaction following-patch testing, suggesting presence of resident, memory T-cells at the site of previous Wells syndrome reactions'. The follow-up information was received on 3 August 2018. This case has been reported in full article. Upon follow-up, the case has been upgraded to serious due to hospitalization after each occurrence. Age of onset was added as 2 years. Additional information was provided. At the age of 2-year, 10 days after receiving the hepatitis A/B vaccine and at the age of 3-year, 17 days after receiving the hepatitis A/B vaccine, the patient experienced erythematous vesicular plaques, ulceration, oedema, and pruritus on the left foot and ankle. On each occasion, he was systemically well but was admitted to the hospital and treated for presumed cellulitis. Medical history included eczema and an episode of hand-foot-mouth disease. Family history included food allergies. At the age of 4 years, 10 days after receiving the tetanus, diphtheria, pertussis, and polio and measles, mumps, rubella, and varicella vaccines, the patient experienced erythematous vesicular plaques, ulceration, oedema, and pruritus on the left foot and ankle. On the third episode, a biopsy was performed. Biopsy showed a basket-weave appearance of the stratum corneum, flame figures, and superficial and deep perivascular and interstitial mixed-cell infiltrate (eosinophils and lymphocytes), suggesting Wells syndrome. He was patch tested to neomycin, polymyxin B, formaldehyde 1%, phenoxyethanol, glutaraldehyde, aluminum hydroxide, and polysorbate 20. A 1+ reaction to aluminum hydroxide and neomycin was present at 96 hours. He developed a recall rash within 48 hours of patch testing. This eruption was less severe than the previous three vaccine-triggered Wells syndrome reactions, consisting of erythematous plaques with no vesicles. The previous episodes of Wells syndrome were limited to the left foot, whereas this recall reaction occurred on both feet, with a more severe reaction on the left foot. He was treated with mometasone furoate 0.1% cream twice a day. The current plan is to continue with standard vaccination schedules and consider prophylactic systemic or topical steroids before vaccination with neomycin-containing or aluminum hydroxide-containing products if no alternatives are available. Pretreatment with systemic steroids must be used with caution, because it can blunt the immunogenicity of the vaccine. The author commented, "Our case supports the hypothesis of CD4+ T-cell involvement in the disease pathogenesis. In our case, the positive patch test suggests the presence of circulating memory CD4+ T cells specific to neomycin and aluminum hydroxide. The patient also had a recall reaction on the left foot after patch testing, suggesting the presence of resident memory CD4+ T-cells at the site of previous Wells syndrome reactions, comparable with a deep dermal contact dermatitis". Lab Comments: Lab tests were performed on an unspecified date. Biopsy results a basket-weave appearance of the stratum corneum, flame figures, and superficial and deep perivascular and interstitial mixed-cell infiltrate (eosinophils and lymphocytes), suggesting Wells syndrome. Patch testing was performed to neomycin, polymyxin B, formaldehyde, phenoxyethanol, glutaraldehyde, aluminum hydroxide, and polysorbate 20 (Tween 80). A 1+ reaction was observed to neomycin and aluminum hydroxide, along with a recall reaction of Wells syndrome of the feet bilaterally.