Skin and hair

Small trials found minor side effects such as skin irritation, in under 5% over 4 weeks in one fibromyalgia trial and 30% over 6 months in another.

Shown to raise side effects such as diarrhea, vomiting and rash against placebo, one extra person affected for every 8 to 24 treated, depending on the infection.

Shown to raise genital yeast infections about fivefold, to about 4% to 6% of people against about 1% on placebo, and to about 11% of women on canagliflozin.

Shown in about 9% of patients over a course of acupuncture, most often bleeding, bruising or pain at the needle site.

Shown to raise rash, in 4% to 5% against 1% on placebo in depression trials. Severe allergic reactions were reported during trials and after approval.

Shown to raise headache, stomach pain, rash, diarrhea and muscle spasms over placebo, and twice as many women stopped for side effects as on placebo.

Shown to raise hair loss or thinning: 3.5% on both Myfembree and Oriahnn, against 0.8% and 1.0% on placebo. Whether it reverses is unknown.

Shown to raise rash against placebo in label trials, 10% against 5% in epilepsy, though a meta-analysis found no clear difference from comparison drugs.

Shown to cause allergic skin reactions such as itching and hives in about 1.5% on glyburide and under 1% on glimepiride in trials.

Injection site reactions occurred in 2% to 7%, more often than with liraglutide or semaglutide, and rose with dose.

Shown to raise hot flashes, 6.5% against 2.6% on placebo at 12 weeks, along with vaginal discharge, muscle spasms and sweating.

One trial found rash in 10% on allopurinol against 2% on placebo. The label calls skin rash the most frequent adverse reaction.

Limited evidence: darkening of the face, gums or breasts occurred in 1% of women at labeled doses and 38% with daily dosing. It did not always fade.

Limited evidence: in a self-report survey, 3.1% to 5.5% reported digestive symptoms, and fewer reported muscle or skin symptoms.

Limited evidence: allergic reactions occurred in 1% to 2% on eptinezumab against none on placebo. Labels report rash, swelling and anaphylaxis after approval.

The label states valproate more than doubles lamotrigine levels, and rash needing hospitalization occurred in 1% of trial patients taking both against 0.16% without valproate.

One trial found low blood pressure in up to 6% and abnormal skin sensation in up to 7%, against 1% or less on placebo.

FDA states lamotrigine has caused life-threatening rashes, including Stevens-Johnson syndrome, in about 0.3% of adults in epilepsy trials and 0.08% to 0.13% in bipolar trials.

One trial found severe rash in 0.26% on clopidogrel against 0.10% on aspirin, and severe diarrhea in 0.23% against 0.11%.

The label reports systemic allergic reactions in 0.5% of adults in trials and injection site reactions in 0.5% against 0% on placebo, with postmarketing anaphylaxis.

One trial reported one allergic event in the garden among 145 people given a community garden plot.

The label warns of serious rash, including Stevens-Johnson syndrome. In children's trials 0.8% stopped for rash, against none on placebo. Modafinil is not approved for children.

The label warns of serious and sometimes fatal skin reactions in about 5 in 10,000 people, with higher risk in carriers of the HLA-B*58:01 gene.

Linked to more non-melanoma skin cancer, mainly squamous cell carcinoma, rising with cumulative dose. The label puts the excess at about 1 case per 16,000 people a year.

The label warns of necrosis or gangrene of skin and other tissues in fewer than 0.1% of people, usually within days of starting.

Shown to raise skin tingling, about 9 times the odds on placebo. It was the only side effect reported across 101 studies.

Linked to 25% higher odds of acne with any dairy against none, in pooled observational studies of people aged 7 to 30, with the strongest link for skim milk.

Shown to double adverse events against control, more than half of them skin dryness. Dry lips, dry skin and dry eyes are among the most frequent effects on the label.

Linked to more melanoma with more sunburns and with intermittent sun exposure in three meta-analyses. Heavy continuous outdoor work showed an inverse link.

Linked to more squamous and basal cell skin cancer in outdoor workers, about 77% and 43% higher odds, in two meta-analyses.

The labels warn of serious, occasionally fatal allergic reactions. In proven penicillin allergy, cross-reaction to cephalosporins ranged from 2% to 16%, highest with a shared side chain.

Shown to cause more adverse events than no treatment in pooled trials, mostly mild and temporary, with no significant difference from sham cupping.

Shown to raise androgenic side effects, mainly acne, about 3.8 times the odds on placebo in menopausal women.

Shown to raise mild adverse events in children, with rash in 7.1% of treated infections against 2.7% on placebo in one trial.

Garlic breath and body odor were the most common complaints in trials. Case reports describe allergic reactions and skin burns from fresh garlic.

Linked to about 2.9 times the odds of Stevens-Johnson syndrome or toxic epidermal necrolysis on lamotrigine in people carrying HLA-B*1502, mostly studied in Asian populations.

Shown to raise acne, hair growth and weight in women. Oral testosterone raised LDL cholesterol, while other routes did not change lipids.

The label warns that acetaminophen may rarely cause serious skin reactions, including Stevens-Johnson syndrome and toxic epidermal necrolysis, which can be fatal.

Case reports: infections were the most common complication in 294 published acupuncture adverse event cases from 2000 to 2011, mostly bacterial.

The label warns stimulants are associated with peripheral vasculopathy, including Raynaud's phenomenon, usually intermittent and mild, with rare skin ulceration. It gives no rate.

The label warns that allopurinol may strengthen warfarin, and that thiazide diuretics, ampicillin and amoxicillin may raise the risk of skin rash.

The doxycycline label warns of exaggerated sunburn, irritation and ulcers of the esophagus, and raised pressure inside the skull, which can threaten vision.

The labels report that a high percentage of people with mononucleosis who take amoxicillin develop a red skin rash.

FDA states severe itching has been reported within days of stopping cetirizine or levocetirizine after long-term use, in 209 cases worldwide. It called the reaction rare.

Case reports: FDA held three reports for injected BPC-157, including injection site swelling, shortness of breath and skin darkening. FDA states it is unclear whether BPC-157 caused them.

The labels report that people sensitized to the clonidine patch may develop a widespread rash, hives or swelling when switched to clonidine tablets. They give no rate.

Case reports: burns, blisters, lasting skin discoloration, scars and infections after cupping, and rare bleeding inside the skull after cupping on the scalp.

Case reports: rare allergic reactions, which may be severe. Gastrointestinal upset and rash were the most frequent adverse events reported.

FDA states it received 32 reports linked to compounded topical finasteride, including sexual and mood effects, most continuing after the product was stopped.

The label warns of angioedema and anaphylaxis with both drugs, and of a multiorgan hypersensitivity reaction with gabapentin that has been fatal. It gives no rate.

Case reports: glucosamine products drew the most supplement reports in Singapore, mainly rash, itching, hives and swelling.

Case series: 85 hot water bottle burns at one UK burns unit over 9 years, 8% needing skin grafts, and 88 at one German center, mostly second-degree and in women.

Case reports: long-term heating pad use caused erythema ab igne, a mottled brown rash. Rare reports describe skin cancer arising in these patches.

FDA states improper implant insertion raises the risk of complications, including nerve injury, scarring and migration into blood vessels, so Nexplanon is available only through a restricted program.

Case reports: a vasculitic rash attributed to ginkgo, horny goat weed or both, taken together.

The label warns hydroxyzine may rarely cause acute generalized exanthematous pustulosis, a serious rash with fever and pustules. It gives no rate.

The label reports severe, life-threatening generalized allergy including anaphylaxis with insulin, and redness, itching and swelling at injection sites. It gives no rate.

Case reports: the label describes Stevens-Johnson syndrome and toxic epidermal necrolysis after approval, some fatal. One case led to withdrawal in trials.

Limited evidence: in one trial four people dropped out for abdominal discomfort, nausea and rash. Trials were too small to estimate rates.

Limited evidence: injection-site redness, itching and bleeding were reported with GLP-1 drugs, rising with dose. Liraglutide-specific rates were not given.

The label reports severe skin reactions after mirtazapine, including drug reaction with eosinophilia and systemic symptoms, Stevens-Johnson syndrome and toxic epidermal necrolysis. It gives no rate.

One trial found more serious gut, muscle, skin, infection and bleeding events with niacin plus laropiprant. EMA suspended these products in 2013.

The label warns of severe skin reactions and of cutaneous and systemic lupus reported with proton pump inhibitors, mostly cutaneous lupus. It gives no rate.

One trial found hair loss and mild dermatitis more common on selenium in men.

Case reports: 201 people who took a supplement with 200 times its labeled selenium had diarrhea, fatigue, hair loss and nail changes.

Limited evidence: brief facial flushing and injection site pain were the most often reported side effects.

Case reports: FDA identified 55 cases of a necrotizing infection of the genital area in people on SGLT2 inhibitors over six years, with no rate.

Case reports: one report of skin and gum darkening with a product combining TB-500 and BPC-157. FDA found no other case reports.

The label reports decreased sweating and raised body temperature, mostly in children and some after hot weather, occasionally needing hospital care. It gives no rate.

The label reports Stevens-Johnson syndrome, toxic epidermal necrolysis, DRESS, anaphylaxis and angioedema with topiramate. It gives no rate.

The labels warn of heightened sunburn susceptibility on topical retinoids. They give no rate.

The tazarotene label warns of added sun sensitivity with thiazide diuretics, tetracyclines, fluoroquinolones, phenothiazines and sulfonamides.

Case reports: the adapalene label lists anaphylaxis, swelling of the face, eyelids and lips, and itching after approval. The tretinoin label calls true contact allergy rare.

The Renova label reports atypical skin cell changes and more elastic tissue damage in some patients using tretinoin 0.05% for longer than 48 weeks, of unknown significance.

The label warns of fatal and serious calciphylaxis, and of cholesterol microemboli that can cause purple toes syndrome. It gives no rate.

The label lists hepatitis and raised liver enzymes, allergic reactions, rash, hair loss, nausea and diarrhea among other adverse reactions. It gives no rates.

Linked to skin reactions at about one event per eight weeks of sensor wear in trials of people with diabetes, with 1.5% rated severe.

FDA states it has not cleared or approved any whole-body cryotherapy device for medical treatment, and names asphyxiation, frostbite, burns and eye injury as hazards.

Two dose-finding trials found blistering and prolonged redness at red light doses of 480 to 640 J/cm², with darker skin reacting at lower doses.

Case series: a Finnish burn center attributed one in four of its burn patients to the sauna, and 54% of those burns needed surgery.

Case reports: a cold burn from liquid nitrogen sprayed on a 71-year-old man's back, and cold panniculitis in a 47-year-old man after sessions.

Case reports: allergic contact dermatitis from wearable device materials, with acrylates, methacrylates and colophonium the allergens most often found on patch testing.