There are all sorts of things we like bringing back from our holidays: tacky souvenirs, photos and videos – even unfortunate tan lines.But what if you return from a trip with rashes, spots or unexplained bumps on your skin? When should you worry, and when are they simply an unwelcome part of the holiday package?’Rashes that appear suddenly and spread quickly, look bruised or purple, form blisters, or develop a clear edge or target-like pattern tend to worry people more,’ explains Dr Dominic Greenyer, a GP and director of The Health Suite.’And rightly so – as these can sometimes point to infections or allergic reactions rather than simple irritation,’ he adds.If you develop symptoms alongside any rashes or spots – such as fever, spreading redness, pain, swelling around the face, difficulty breathing or confusion – seek medical help immediately.Otherwise, don’t let these spots, rashes or blotches ruin your trip or the memories you’ve made. We’ve sought professional guidance from experts on how to manage any of these common conditions effectively…1. Tiny, itchy red bumpsLikely cause: Heat rashHeat rash usually develops during hot or humid weather and appears as small red bumps or tiny blisters – often in sweaty areas such as the neck, chest, back or skin folds. Many of us return from holiday with unexplained spots or itches. Some, such as mild heat rash, are harmless and will disappear quickly. But others could be a sign of something more seriousAs Dr Tina Tian, consultant dermatologist at Stratum Clinics, explains: ‘It may feel prickly or itchy, but usually settles quickly once the skin cools and dries. If a rash is painful, spreading, persistent or associated with fever, it should be checked out.’2. Itchy red/pink spots, small blisters or blotchy patchesLikely cause: Sun allergyKnown as ‘polymorphic light eruption’, or PMLE, this common skin condition can develop days after exposure to the first strong sun of the year, or after taking a sunny trip.The condition affects between 10-15 per cent of people in the UK, three quarters of whom are women. It usually appears on parts of the arms, legs and chest not regularly exposed to the sun. The ears are also commonly affected.’Avoid sun while you have the rash, and use a SPF 50 broad?spectrum sunscreen,’ says Dr Elise Dallas, from The London General Practice.’Applying moisturisers or calamine will help as will taking oral antihistamines. Short courses of topical or oral steroids can be used if the rash is severe.’ Small pink spots, which usually appear on the arms, could be a result of exposure to strong sun. The condition, known as polymorphic light eruption, is most common in womenYou should see a doctor if the rash doesn’t settle after a week, or if you feel fatigue or joint pains. PMLE is not linked to skin cancer.3. Streaky red patches that blister and leave dark marksLikely cause: Margarita burn (phytophotodermatitis)This skin reaction takes place when citrus juice or certain plant saps come into contact with skin which is then exposed to sunlight.It occurs most commonly at the beach or at poolside barbecues – which is where it gets its exotic name. The reaction causes streaky irregular red patches that can blister and then leave dark marks that can hang around for weeks.’Wash skin and use cool compresses,’ says Dr Dallas. ‘A course of topical steroids and simple pain relief will also help, and you should stay out of the sun to avoid worse pigmentation.’4. Small red or white spots around hair folliclesLikely cause: Holiday folliculitisThis condition is often linked to warm weather, as heat and humidity create the perfect environment for bacteria to thrive. The spots can appear anywhere you find hair on the body, such as the legs, back, chest, face, armpits and groin.’It can be triggered by hot tubs, sweating or friction,’ says Dr Ross Perry, founder and medical director at Cosmedics Skin Clinics. ‘However, if it is painful, spreading or not improving after a week, you should get medical help.’Most cases of folliculitis are mild, though, and should clear up without treatment within seven days. Using a warm, moist washcloth on the affected area should provide some relief.5. Itchy red bumps on swimsuit-covered areasLikely cause: Seabather’s eruptionThis itchy, bumpy rash can break out anything from a few minutes to 24 hours after sea swimming, and is caused by trapped jellyfish or anemone larvae stinging the skin under your swimwear. Despite often being incorrectly referred to as ‘sea lice’, it has nothing to do with either sea or head lice. Seabather’s eruption – caused by jellyfish stinging the skin under swimwear – can be soothed with vinegar, antihistamines or a mild steroid cream’As soon as you can, get out of your swimwear and give your skin a rinse,’ says Dr Dallas. ‘A splash of vinegar can help deactivate any lingering stingers, while a mild steroid cream or an oral antihistamine can calm the itch.’Avoid jumping into a freshwater shower while you’re still wearing your swimsuit, as this can actually trigger further stings.6. Itchy, tingling skin with small, red pimples after swimming in a lake or a lagoonLikely cause: Cercarial dermatitisAlso known as ‘swimmer’s itch’, this condition is caused by an allergic reaction to microscopic parasites in freshwater or seawater, released from infected snails or birds and mammals.It doesn’t happen under swimwear, but rather anywhere on the skin and will likely break out within hours to two?days of swimming in a pond, lake or lagoon.’It’s not a worry unless you develop a fever, or if you scratch and develop signs of infection-spreading redness, or pus,’ says Dr Dallas.Otherwise, cool compresses, oral antihistamines, topical steroids or calamine will help ease the irritation. The condition should settle within a week or two.7. Small, itchy bumps in a rowLikely cause: Bed bugs or flea bitesMemories of your hotel room can come back to bite – literally – if there are bed bugs or fleas. Their bites often appear in lines or clusters, especially around the ankles. By contrast, horsefly bites are larger, painful and can bleed. Bites from fleas or bed bugs tend to appear in clusters. For the most part, these can easily be managed at home, but keep an eye on the area in case you develop an allergic reaction It’s vital to seek medical help if you get any kind of allergic reaction, such as wheezing or swelling, or if a bite becomes infected and you get a high temperature or more swelling.Otherwise, relief can usually be managed at home with cool compresses, oral antihistamines, mild topical steroids and simple painkillers.8. Bullseye rashLikely cause: Tick bite and potentially Lyme diseaseA bacterial infection spread by infected ticks, Lyme disease usually begins with a slowly expanding, red rash spreading outwards over the course of a few days or weeks. It may also develop a ‘bullseye’ appearance.Dr Tian explains: ‘The rash is usually not itchy or painful. However, if you develop flu-like symptoms such as a fever, headache, fatigue or joint aches following a tick bite, you should seek medical help.’By contrast, hypersensitivity ‘bite reactions’ are raised, itchy, and will appear within 48 hours, notes Dr Dallas. Unlike a Lyme rash, these reactions do not continue to expand over several days. Lyme disease usually begins with a slowly expanding red rash, spreading outwards over the course of a few days or weeks – often in the shape of a ‘bullseye’You can reduce the risk of Lyme disease by promptly removing any ticks with fine-tipped tweezers: grasp the tick close to the skin and pull it out steadily, making sure to remove the whole tick.9. White, flat scaly patches Likely cause: Pityriasis (tinea) versicolor, the ‘white patches after sun’This common and harmless skin condition is caused by an overgrowth of a natural yeast that lives on the skin.'[Pityriasis] often becomes noticeable after sun exposure – hence its nickname,’ says Dr Tian. ‘When affected areas fail to tan, they leave pale, darker or pink patches on the chest, back or arms, sometimes with fine scaling.’Treatment usually involves antifungal shampoos, used as a body wash, or creams to reduce amounts of skin yeast. Sometimes, short courses of antifungal tablets might be needed.Once the infection clears, the colour change can take weeks or months to return to normal, but it doesn’t cause scarring or permanent skin damage.10. Intensely itchy, thin, winding red tracks on the feet, buttocks or thighsLikely cause: Cutaneous larva migrans (known as ‘creeping eruption’ from sandy beaches)This skin infection is caused by hookworm larvae and can be picked up from contaminated sand, most commonly on tropical or subtropical beaches.Dr Tian explains: ‘It causes an intensely itchy, winding red rash that appears to move slightly each day under the skin.’Treatment involves prescription antiparasitic tablets or creams, which should rapidly relieve symptoms and clear the infection.’11. Dry, rough scaly patchesLikely cause: Actinic (solar) keratosesThese patches, which are caused by long-term sun exposure, often feel like sandpaper and are usually one to two centimetres in size. Actinic keratoses may develop into a form of skin cancer called squamous cell carcinoma. If you notice new or changing patches, see your GP, urges Dr Dallas They are typically found on the face, ears, backs of the hands, scalp or legs. Sometimes itchy, they are an early sign of skin damage, and so carry a small risk of developing into a form of skin cancer known as squamous cell carcinoma.Treatment may include freezing the patches (cryotherapy), which causes them to blister and fall off over a few weeks, or minor surgery to cut out or scrape away the affected area (done under local anaesthetic, so it shouldn’t be painful). Another option is photodynamic therapy, where a special cream is applied to the skin and activated with a light.Dr Dallas advises seeing your GP if you notice new or changing patches, particularly if a patch bleeds, grows quickly, becomes tender, or develops into a lump or horn.12. Changing molesLikely cause: Potential skin cancerUltraviolet light from the sun is the most common cause of melanoma – the deadliest form of skin cancer. And though most moles are harmless, it’s important to be aware of warning signs if they appear to change. While most moles are harmless, it’s crucial to be aware of warning signs such as their shape or colour appearing to change, as that could be a sign of melanoma (skin cancer)Key things to look out for, according to Dr Tian, are as follows: if the two halves of the mole don’t match; the edges are uneven or irregular; uneven colour (melanomas may have shades of brown, black, tan, pink, red, white or blue); if the mole is larger than 6mm, or changes in size, shape or colour. Dr Tian also highlights the ‘ugly duckling’ sign: ‘This is a mole or mark that looks noticeably different from your other moles. It might be darker, larger, more irregular or simply unusual for you.’Not all skin cancers resemble traditional moles, so keep an eye out for the following: a sore that doesn’t heal; a shiny, pearlescent, or translucent bump; a scar-like area appearing without a previous injury; a painful, scaly, crusty, or raised lump; a rapidly growing lump or nodule (sometimes resembling a mini-volcano) or a red, scaly patch.Dark brown or black changes under the nail that get bigger and spread onto surrounding skin may also be melanoma, and should be checked out immediately.Dr Tian adds that a new mole appearing after the age of 40 is uncommon and should be monitored carefully.