Can vaccination trigger Sweet’s syndrome?

Sweet’s syndrome triggered by vaccination.

There is some medical evidence to show that certain vaccinations can potentially trigger Sweet’s syndrome, but this is incredibly rare, and it is important to take the following information into consideration:

  • Sweet’s syndrome is rare, probably affecting no more than 3 people per 10,000 (Zamanian and Ameri, 2007).
  • It mainly affects adults not children, and only 5% to 8% of cases will be in children (Sharma et al, 2015).
  • In some people, something is needed to trigger the onset of Sweet’s syndrome, but in up to 71% of people with Sweet’s syndrome there is no known trigger (Tam and Ingraffea, 2015).
  • Infection, mainly upper respiratory tract infection, is a more common trigger for Sweet’s syndrome than vaccination. As a result, Sweet’s syndrome tends to be more common in countries where people are more likely to develop infections (Ginarte and Toribio, 2011:120).
  • There have only been 10 cases of Sweet’s syndrome triggered by vaccination reported in medical literature in the past 42 years – globally! In some of these cases, a definite connection between the vaccination and Sweet’s syndrome was not established.
  • Sweet’s syndrome has only been associated with certain vaccinations and not others (see below).

Which vaccinations have been associated with Sweet’s syndrome?

Sweet’s syndrome has been associated with the following vaccinations:

  • Bacillus Calmette-Guerin (BCG or tuberculosis) (Carpentier et al, 2002: 82; Cruz-Velasquez et al, 2016). Two cases. One in 1986, occurring 15 days after vaccination, but the authors of the medical article that reported this did not control the tuberculin (Mantoux) test. One reported in 2002, occurring 10 days after vaccination.
  • Streptococcus pneumonia (Carpentier et al, 2002: 82; Cruz-Velasquez et al, 2016; Pedrosa et al, 2013). Two cases. One reported in 1990, occurring 4 days after vaccination following a splenectomy. One reported in 2013, and the first with the 13-valent conjugate vaccine.
  • Smallpox (Carpentier et al, 2002: 82; Cruz-Velasquez et al, 2016). Two cases reported in 1975, occurring 3 days after vaccination.
  • Influenza (Cruz-Velasquez et al, 2016; Hali et al, 2010, Jovanovic et al, 2005; Tan el al. 2006; Wolf et al. 2009). Four cases. One reported in 2005; in 2006, one case of bullous Sweet’s syndrome following vaccination in a HIV-infected patient; in 2009, neutrophilic dermatosis of the hands occurring 12 hours after vaccination; in 2010, one case of Sweet’s syndrome after H1N1 influenza (swine fluvaccination.

Do vaccinations trigger Sweet’s syndrome because they are toxic, contain toxins or dangerous chemicals?

No, vaccinations do not trigger Sweet’s syndrome because they are toxic, contain toxins or dangerous chemicals, and anyone who tells you this is either lying to you, trying to scare you, or has no understanding of vaccinations or Sweet’s syndrome.

Why do vaccinations trigger Sweet’s syndrome?

Vaccination can trigger Sweet’s syndrome because of hypersensitivity reaction. This is not the same as allergic reaction.

What is hypersensitivity reaction?

Sweet’s syndrome is caused by errors in the innate immune system (the body’s most primitive, ‘hard-wired’ immune system, and a part of the immune system that doesn’t produce antibodies). Because of these errors, in some people with Sweet’s syndrome, their innate immune system responds to antigens (proteins that a part of your immune system called the adaptive immune system sees as a foreign invader and produces antibodies in response to) in a way that it shouldn’t, i.e. is hypersensitive and over-reacts to the presence of infectious, inflammatory, drug, or tumour cell antigens (Bhat et al, 2015: 257; Kasirye et al, 2011: 135). This means that the presence of antigens associated with certain health conditions, medications and vaccinations can potentially trigger Sweet’s syndrome by causing the innate immune system to activate inflammatory cells, particularly white blood cells called neutrophils (Gosheger et al, 2002: 70). This then leads to the symptoms of Sweet’s syndrome.

If I have Sweet’s syndrome should I avoid having vaccinations?

No, most people with Sweet’s syndrome don’t need to avoid having their vaccinations unless they can’t be vaccinated for other medical reasons. However, if the Sweet’s syndrome was initially triggered by a particular vaccination, e.g. influenza, then it would not be advisable to have the same kind of vaccination again.

How do I know if vaccination has triggered my Sweet’s syndrome?

Remember, Sweet’s syndrome triggered by vaccination is incredibly rare, but if it does happen, then symptoms usually develop within hours, days or less commonly, a few weeks after vaccination. Skin lesions sometimes appear at the vaccination site, but this can also happen because of the skin damage caused by having the vaccination (puncture wound from the needle) rather than the vaccine itself. This response is known as pathergy.

Are there other triggers for Sweet’s syndrome?

Yes, and aside from the triggers that have already been mentioned (infection, skin damage, and vaccination), other triggers for Sweet’s syndrome include:

  • Cancer and blood disorders in 15-20% of cases, e.g. solid tumours, and myelodysplastic syndrome which may progress to acute myeloid leukaemia (Chen et al, 2016).
  • Inflammatory bowel disease, e.g. Crohn’s disease and ulcerative colitis (Cohen, 2007).
  • Autoimmune conditions, e.g. rheumatoid arthritis and systemic lupus erythematosus.
  • Medications in up to 5% of cases.
  • Pregnancy in up to 2% of cases. This is probably associated with hormonal changes, but further research is required.
  • Overexposure to sunlight or ultraviolet (UV) light. This can sometimes trigger Sweet’s syndrome, but we are not entirely sure why this happens.


Bhat, Y., Hassan, I., Sajad, P., Akhtar, S. and Sheikh, S. (2015) Sweet’s Syndrome: An Evidence-Based Report. Journal of the College of Physicians and Surgeons – Pakistan, Jul;25(7):525-7 (PubMed).

Carpentier, O., Piette, F. and Delaporte, E. (2002) Sweet’s syndrome after BCG vaccination. Acta Dermato-Venereologica;82(3):221 (PubMed).

Chen, S., Kuo, Y., Liu, Y., Chen, B., Lu, Y. and Miser, J. (2016) Acute Myeloid Leukemia Presenting with Sweet Syndrome: A Case Report and Review of the Literature. Pediatrics and Neonatology (online).

Cohen, P. (2007) Sweet’s syndrome – a comprehensive review of an acute febrile neutrophilic dermatosis (online).

Cruz-Velásquez, G., Pac Sha, J., Simal Gil, E. and Gazulla, J. (2016). Aseptic meningitis and anti-β2-glycoprotein 1 antibodies in Sweet syndrome. Neurologia (Barcelona, Spain), Jul 21 (0nline). Article in Spanish, use translate

Ginarte, M. and Toribio, J. (2011) Sweet Syndrome. In Dr. Fang-Ping (Ed.) Autoimmune Disorders – Current Concepts and Advances from Bedside to Mechanistic Insights. Croatia or China: Intech, pp. 119-132 (PDF). 

Gosheger, G., Hillman, A., Ozaki, T., Buerger, H. and Winklemann, W. (2002) Sweet’s Syndrome Associated With Pigmented Villonodular Synovitis. Acta Orthopædica Belgica, Feb;68(1):68-71 (PubMed).

Hali, F., Sbai, M., Benchikhi, H., Ouakadi, A. and Zamiati, S. (2010) [Sweet’s syndrome after H1N1 influenza vaccination]. Annales de Dermatologie et de Venereologie,  Nov;137(11):740-1 (PubMed).

Jovanovic, M., Poljacki, M., Vujanovic, L. and Duran, V. (2005) Acute febrile neutrophilic dermatosis (Sweet’s syndrome) after influenza vaccination. Journal of the American Academy of Dermatology, Feb;52(2):367-9 (PubMed).

Kasirye, Y., Danhof, R., Epperla, N. and Garcia-Montilla, R. (2011) Sweet’s Syndrome: One Disease, Multiple Faces. Clinical Medicine & Research, Nov;9(3-4):134-136 (online).

Pedrosa, A., Morais, P., Nogueira, A., Pardal, J. and Azevedo, F. (2013) Sweet’s syndrome triggered by pneumococcal vaccination. Cutaneous and Ocular Toxicology, Sep;32(3):260-1 (PubMed).

Sharma, A., Rattan, R., Shankar, V., Tegta, G. and Verma, G. (2015) Sweet’s syndrome in a 1-year-old child. Indian Journal of  Paediatric Dermatology;16:29-31 (online).

Tam, C. and Ingraffea, A. (2015) Case Letter: Sweet Syndrome Presenting With an Unusual Morphology. Cutis, Aug;96(2):E9-E10 (online).

Tan, A., Tan. H., and Lim, P. (2006) Bullous Sweet’s syndrome following influenza vaccination in a HIV-infected patient. International Journal of Dermatology, Oct;45(10):1254-5 (PubMed). 

Zamanian, A. and Ameri, A. (2007) Acute febrile neutrophilic dermatosis (Sweet’s syndrome): a study of 15 cases in Iran. International Journal of Dermatology, Jun;46(6):571-4 (PubMed).

Wolf, R., Barzilai, A. and Davidovici, B. (2009) Neutrophilic dermatosis of the hands after influenza vaccination. International Journal of Dermatology, Jan;48(1):66-8 (PubMed).

© 2012-2017 Sweet’s Syndrome UK

Pregnancy-associated Sweet’s syndrome

Links checked on 30/03/17.

Can Sweet’s syndrome be triggered by pregnancy?

Yes, but it’s rare. Only about 2% of cases of Sweet’s syndrome are associated with pregnancy (Chebbi and Josephine, 2014).

How many cases have been reported?

By the end of 2014, there had been at least 10 cases of pregnancy-associated Sweet’s syndrome reported in literature (Chebbi and Josephine, 2014; Serrano-Falcón and Serrano-Falcón, 2010: 559). However, it is possibly being under-reported and underdiagnosed due to:

  • A lack of awareness and knowledge of pregnancy-associated Sweet’s syndrome.
  • The variability of Sweet’s syndrome symptoms, and on rare occasions, skin lesions not being present. This means that a diagnosis of Sweet’s syndrome may be not be considered or dismissed.
  • Pregnancy affecting blood results (Serrano-Falcón and Serrano-Falcón, 2010: 559). This means that the blood results of someone with pregnancy-associated Sweet’s syndrome might show something different from what you would expect to find.

Can pregnancy-associated Sweet’s syndrome be confused with other skin conditions?

Yes. It may be confused with urticarial vasculitis, eosinophilic panniculitis, and herpes gestationis (Serrano-Falcón and Serrano-Falcón, 2010: 558).

What causes pregnancy-associated Sweet’s syndrome?

We are not entirely sure what causes pregnancy-associated Sweet’s syndrome in some women, but it may be linked to hormonal changes and increased progesterone or oestrogen levels (Serrano-Falcón and Serrano-Falcón, 2010: 558).

What are the symptoms of pregnancy-associated Sweet’s syndrome?

Read about the symptoms of Sweet’s syndrome here.

How  is it diagnosed?

Read about how Sweet’s syndrome is diagnosed here.

How is pregnancy-associated Sweet’s syndrome treated?

  • Systemic corticosteroids (steroids) such as Prednisone are the main form of treatment. Treatment should start with 1mg/kg/day or less, in a single dose taken in the morning, and should be tapered off until the minimum effective dose is determined (Serrano-Falcón and Serrano-Falcón, 2010:559).
  • Steroid creams can be used if the skin lesions are small and in one area, and if there are few other symptoms.
  • Other treatment options to be considered include colchicine and indomethacin.

Are there treatments that should be avoided?

Yes. Certain medications that are sometimes used to treat Sweet’s syndrome are not safe to use during pregnancy. These include:

  • Potassium iodide.
  • Immunosuppressants such as ciclosporin, azathioprine, and methotrexate.
  • Biologics such as infliximab, adalimumab, and etanercept.

Does Sweet’s syndrome cause complications or affect how you will be cared for during pregnancy?

Sweet’s syndrome does not tend to cause complications during pregnancy or affect the baby. However, as a precaution, your doctor or nurse will need to monitor you as for an at-risk pregnancy.

Can pregnancy-associated Sweet’s syndrome come back once it has been treated?

Pregnancy-associated Sweet’s syndrome normally settles after treatment. This may take up to 7 days, weeks or months. Sometimes, the Sweet’s syndrome doesn’t completely settle until delivery of the baby, and may flare-up again with later pregnancies (Chebbi and Josephine, 2014).

N.B. There are some cases of pregnancy-associated Sweet’s syndrome that have not resolved after delivery, but have not been reported in literature. However, this may be for reasons such as infection, underlying illness, or medication.


Chebbi, W. and Josephine M. (2014) Sweet syndrome during pregnancy: a rare entity not to ignore. The Pan African Medical Journal, 18: 185 (online). Article in French. Use translate.

Serrano-Falcón, C. and Serrano-Falcón, M. (2010) Sweet’s syndrome in a pregnant women. Actas Dermo-Sifiliograficas, Jul;101(6):558-9 (online).

Further information.

Giovanna Brunasso, A. and Massone, C. (2008) Clinical images. Sweet syndrome during pregnancy. CMAJ: Canadian Medical Association Journal, Oct 21;179(9):967 (online).

© 2012-2017 Sweet’s Syndrome UK

Smoking and Sweet’s Syndrome

Updated 3/04/17.

Should you stop smoking if you have Sweet’s syndrome?

Ideally, yes.

If you are diagnosed with Sweet’s syndrome, it is very important to try to stop smoking for the following reasons:

  • Smoking is bad for overall health.
  • Smoking is bad for the skin.
  • Some people with Sweet’s syndrome are taking medication or develop their Sweet’s syndrome secondary to a condition that weakens or severely weakens their immune system. This means that they are more likely to develop infections, and infection can sometimes trigger Sweet’s syndrome. This is because some people with Sweet’s syndrome experience hypersensitivity reaction (not the same as allergic reaction). Read more here.
  • Smoking increases your risk of developing a respiratory infection, and upper respiratory tract infection is the commonest infectious trigger for Sweet’s syndrome.

What are upper respiratory tract infections?

Upper respiratory tract infections are illnesses caused by an acute infection which involves the upper respiratory tract: nose, sinuses, pharynx, larynx, and bronchi (airways going into the lungs). They commonly include tonsillitis, pharyngitis, laryngitis, sinusitis, bronchitis, otitis media (middle-ear infection), flu, and the common cold.

What are the symptoms of an upper respiratory tract infection?

A cough is the most common symptom of an upper respiratory tract infection. Other symptoms include:

  • Fever.
  • Headaches.
  • Stuffed or runny nose.
  • Sneezing.
  • Sore throat.
  • Muscle aches and pain

The symptoms of an upper respiratory tract infection usually pass within one to two weeks.

Smoking is bad for the skin. Why is this?

Smoking is bad for the skin because it can (Simpkin and Oakley, 2016):

  • Speed-up the skin ageing process. Ageing of the skin means that it can sag; develop wrinkles and lines; becomes dry and coarse; have uneven skin colouring; blood vessels can be more prominent.
  • Slow-down wound healing which means that skin injuries and surgical wounds will take longer to heal.
  • Increase your risk of skin or wound infection.
  • Double your risk of skin cancer (squamous cell carcinoma), and increase your risk of developing other cancers. 75% of cases of oral cancer and lip cancer occur in smokers.
  • Increase your risk of developing the disabling skin condition palmoplantar pustulosis which mainly affects middle-aged women, particularly those who smoke (more than 90% of cases).
  • Increase your risk of developing other skin conditions, e.g. psoriasis, hidradenitis suppurativa and cutaneous lupus erythematosus.
  • Make skin conditions worse and more difficult to treat.
  • Make certain medications less effective, e.g. insulin, analgesics, antipsychotics, and anticoagulants.


Simpkin, S. and Oakley, A. (2016) Smoking and its effects on the skin. DermNet NZ (online). Originally published in 2010, and updated by Professor A. Oakley in Nov 2016. Accessed on 3/04/17.

Further information.

NHS Choices (2016) Live Well – Stop Smoking (online). Accessed 3/04/17.

© 2012-2017 Sweet’s Syndrome UK