Antibiotics And Sun Exposure

The warmth of the sun feels so good, especially during winter skiing, hiking, swimming or just getting tanned under the sun on the seaside. However, certain medicines like taking some antibiotics make it challenging and less fun.

These medicines contain ingredients that may cause sun sensitivity or photosensitivity (which makes a person sensitive to sun exposure). It leads to sunburn-like symptoms, rash etc.1 This article will review different types of sun sensitivity reactions, their mechanism, and some protective methods and management actions to increase the comfort level in day to day-to-day life of patients.


Overview of antibiotics

In modern medical practice, antibiotics are commonly used as a treatment plan by health care providers. In ancient times it wasn't the case and patients were treated with different approaches. Bacteria, viruses, fungi, and parasites are the infection-causing agents and have medical significance. Antibiotics are drugs used to treat bacterial infections. 

Several factors like patient age, medication allergies, kidney and liver function, previous medical history, the presence of an immunocompromised state, and recent antibiotic dosage need to be considered before prescribing antibiotics. antibiotics are an important part of today's treatment yet it has many disadvantages and needs to be consumed according to doctors prescription.2

Interaction between antibiotics and sun exposure

Photosensitivity reactions

1. Definition and explanation

Photosensitizers are the medicines that cause reactions to the sun. On some structural and molecular levels, the substances in these medications can destabilize. Once destabilisation occurs, in the skin chemicals build up, resulting in increased sun sensitivity. Sun sensitivity is of two types

  • Photoallergy - Photoallergy is mostly caused by topical medications applied on the skin's surface. UV light changes the molecular structure of topical medications and triggers an immune response by the formation of small molecules called hapten7
  • Phototoxicity - It is a more common type of photosensitivity. Phototoxicity is frequently caused by oral and injectable medications and less commonly by topical medications

It affects the dermis and epidermis of the skin. Phototoxicity forms blisters, redness, and peeling in some severe cases. On top of that skin can feel hot, itchy and uncomfortable.3

2. Common antibiotics causing photosensitivity

Sulfa antibiotics (trimethoprim-sulfamethoxazole), ciprofloxacin, tetracycline, and doxycycline are the most commonly prescribed antibiotics which increase the risk of photosensitivity. One needs to be more careful while taking these antibiotics or even after you finish them.4

3. Symptoms of photosensitivity

Erythema, swelling, blisters, exudation, peeling, burning, itching and hyperpigmentation on the skin are some of the symptoms of drug-induced photosensitivity.5

Mechanism of photosensitivity

The Flow chart below shows the brief mechanism of photosensitizers in phototoxicity and photoallergy.6

1.) Photoallergy

Here in this reaction, photosensitizer absorbs photons which are later converted into reactive chromophores. Within the dermis and epidermis chromophore binds to a protein and forms a complete antigen, this is also called haptenization. The antigen is then processed by Langerhans cells and presented to T cells present in lymph nodes via molecule MHC II (major histocompatibility complex). Hence photoallergy reaction is a cell‐mediated type IV hypersensitivity reaction.6

2.) Phototoxicity

In phototoxicity cellular damage takes place through non-immunological pathways. It is divided into two types.

  • Oxygen-dependent or photodynamic phototoxicity:

Here in this reaction, photosensitizers are present in a triple excited state and by electron energy transfer return to the ground state. 

It results in the production of free radicals, which can interact with ground-state oxygen. 

Due to this oxidation damage to the cell takes place as a result of the formation of reactive oxygen species (ROS) such as superoxide anion, hydrogen peroxide, and hydroxyl radical.

  • Oxygen-independent or non-photodynamic phototoxicity:

 In this, the direct cellular damage happens by excited photosensitizers in deoxygenated conditions. In one pathway there is a covalent binding between the drug or its chemical compound and cell macromolecules.

In another pathway, there can be a decomposition of an excited photosensitizer and the product obtained through this decomposition acts as a new photosensitizer.

Now damaged cell components lead to the formation of erythrogenic mediators. Hydrophilic photosensitizers cause membrane injury while lipophilic ones damage intercellular components.5

Difference between photoallergy and phototoxicity

Photoallergy- A typical “crescendo” pattern is seen in photoallergy where cutaneous changes increase during the time of disease, typically 48 to 72 hours after the occurrence of the symptoms. This is called the “crescendo pattern”. 

Phototoxicity- It shows a “decrescendo” pattern in which symptoms are predominantly seen after 24 to 48 hours of sun exposure and gradually decrease after some days.6

Protective methods and management

Following are some ways to protect from sun sensitivity

1. Wear sunscreen

Whenever you are outside, cover exposed skin with a broad-spectrum sunscreen with a minimum SPF value of 30 or higher, this protects from both ultraviolet radiation A and B. 

2. Minimize sun exposure

It is not necessary to stay at home for the entire time but avoid the outdoor time when it looks too hot outside. One can also use the Sun Index App to monitor sun exposure time. 

3. Cover skin with appropriate clothing

Appropriate clothing is also important to protect from sun exposure. 

The following points are recommended by The American Academy of Dermatology:

  1. Wear dark colour and thick material containing a long-sleeved shirt and pants
  2. One should always wear sunglasses
  3. Always remember to wear shoes and avoid using sleepers and sandals
  4. It is also important to protect your face with a wide hat, it will also give protection to the ear and neck3


Management of photosensitivity must be done by stopping the causative drug. In cases where the drug cannot be avoided or indispensable it is important to reduce the dosage or UV exposure. Topical steroids are an option for acute phototoxic cases. In photoallergic patients, it can be treated with topical steroids, antihistamines and NSAIDs.

Along with this protective measures are always mandatory to increase comfort.6


Can antibiotics cause sun sensitivity?

Yes, some antibiotics like sulfa antibiotics (trimethoprim-sulfamethoxazole), ciprofloxacin, tetracycline, and doxycycline can cause sun sensitivity in some patients.

How long does antibiotic sensitivity last?

 It can vary from person to person and also according to the type of medication taken. They can last for a week or more. In severe cases, symptoms can last for weeks or months.

Is there any treatment plan for sun sensitivity?

Once there is a sign of photosensitivity one must visit the concerned physician, they will either change the type of antibiotics prescribed or will give some treatment options to treat sensitivity.

What are the symptoms of sun sensitivity or photosensitivity?

Erythema, swelling, blisters, exudation, peeling, burning, itching and hyperpigmentation are some common symptoms of sun sensitivity or photosensitivity.


Antibiotic-induced sun sensitivity is a concerning medical problem. It can cause phototoxic or photoallergic reactions. Nowadays the incidence of photosensitivity reactions is constantly increasing. Photosensitivity is the result of different mechanisms and processes as discussed above.5 One must visit a doctor at the first sign of photosensitivity.

They will find a solution to it and guide accordingly by either switching the antibiotics or by giving some topical ointments to minimize the symptoms. Typically it is a temporary problem. But one needs to watch out for even minor symptoms.3


  1. Research C for DE and. The sun and your medicine. FDA [Internet]. 2018 Nov 3 [cited 2023 Dec 14]; Available from:
  2. Patel P, Wermuth HR, Calhoun C, Hall GA. Antibiotics. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 [cited 2023 Dec 12]. Available from:
  3. Author GP. Antibiotics can potentially cause sun sensitivity and sun allergy. [Internet]. Sun IndexTM | Optimizing Sun Exposure | Balance UV exposure and vitamin D. 2020 [cited 2023 Dec 12]. Available from:
  4. MD LJG. Antibiotics and sun exposure: understanding the connection [Internet]. Live Freely by EltaMD, Inc. 2021 [cited 2023 Dec 16]. Available from:
  5. Kowalska J, Rok J, Rzepka Z, Wrześniok D. Drug-induced photosensitivity—from light and chemistry to biological reactions and clinical symptoms. Pharmaceuticals (Basel) [Internet]. 2021 Jul 26 [cited 2023 Dec 14];14(8):723. Available from:
  6. Hofmann GA, Weber B. Drug‐induced photosensitivity: culprit drugs, potential mechanisms and clinical consequences. J Dtsch Dermatol Ges [Internet]. 2021 Jan [cited 2023 Dec 14];19(1):19–29. Available from:
  7. Erkes, Dan A., and Senthamil R. Selvan. ‘Hapten-Induced Contact Hypersensitivity, Autoimmune Reactions, and Tumor Regression: Plausibility of Mediating Antitumor Immunity’. Journal of Immunology Research, vol. 2014, 2014, p. 175265. PubMed Central,
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Dr. Kirti Vishwajeet Pardeshi

Bachelor's degree, BDS, Maharashtra University of Health Sciences

Dr. Kirti Pardeshi, a highly skilled dental surgeon with six years of extensive clinical expertise. Apart from her impactful clinical background, she has dedicated several years to serving as a biology faculty member. Fueled by a passion for knowledge, patient care and research, Dr. Pardeshi earned certification in clinical research, delving into the systematic investigation that underpins medical advancements.

Presently, she is deeply committed to the pursuit of a postgraduate degree in medical writing, pushing the boundaries of her expertise.

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