I cannot tell if you are referencing sunless tanning lotions or sun tan lotions with or without sun blocking agents. Most of the contact dermatitis with sun tan products are due to parabens, including methyl-, ethy-, propyl-, butyl-, and benzylparaben. Parabens are included in the preliminary patch testing.
I sent your question to Dr. Luz Fonacier, Professor of Medicine Winthrop University and lead author of the practice parameter devoted to contact dermatitis. Her comments follow:
"Sunless tanning lotions have become popular in recent years due to concerns regarding ultraviolet radiation from the sun. However, adverse reactions including contact dermatitis have been reported.
Free Radicals: dihydroxyacetone (DHA), a sugar that degrades to free radical products upon exposure to light, is the compound in sunless tanning products that reacts with your skin to darken it.
Still the most common contact dermatitis in essential oils are the fragrances, which can cause allergic contact dermatitis or photocontact dermatitis."
I have enclosed a copy of the section from the practice parameter on contact dermatitis concerning reactions to sunscreens.
Summary Statement 33: Suspect the diagnosis of photoallergic
CD to cosmetics when eczema occurs in a light exposed
distribution following the use of a skin care product
or cosmetic, including sunscreens. [Strength of Recommendation:
Strong; C Evidence]
Some cosmetic ingredients may only cause an ACD after
exposure to UV radiation. Photo-allergic CD typically affects
sun-exposed areas such as the face, the ‘‘V’’ of the anterior neck,
the dorsal hands, and forearms. It typically spares the upper
eyelids, upper lip, and submental and postauricular areas. Before
evaluation for photo-allergic CD, one should rule out phototoxic
drug eruption, photo-allergic drug eruption, and systemic disease
such as lupus erythematosus.
The prevalence of allergic reactions to sunscreens may
continue to increase as the use of sunscreen continues to become
more widespread. Allergic and photo-allergic reactions have been
reported with several chemical sunscreen families.173,174
Sunscreens have traditionally been divided into chemical
absorbers (UVB [290-320 nm], UVA II [321-340 nm], and
UVA I [341-400 nm]) and physical blockers.
Sunscreens are often overlooked as a cause of CD, because
other excipients (fragrances, formaldehyde releasers, preservatives,
vitamin E, and lanolin alcohol)175 are more
frequently implicated. Sunscreen sensitization is much higher in
individuals referred for evaluation of photosensitivity.176 The
most common cosmetic sunscreen agents used are listed in
Physical ultraviolet light blockers
Titanium dioxide and zinc oxide are the most common
physical UV blockers used today and have not been reported to
cause contact dermatitis or photo-allergy.
TABLE IV. The most common cosmetic sunscreen agents
Cinnamates Octyl dimethyl
Titanium dioxide Anthranilates
Butyl methoxydibenzoylmethane Zinc oxide
or avobenzone (Parsol 1789)
In summary, "tanning lotions" include both suntan lotions, sunblocks and sunless tanning lotions.
1. Jackson, Edward M. "Tanning Without Sun: Accelerators, Promoters, Pills, Bronzing Gels, and Self-Tanning Lotions." Dermatitis 5.1 (1994): 38.
2. Fonacier L, Bernstein DI et al. Contact dermatitis: A practice parameter--Update 2015. JACI In Practice 2015;3:S1-39.
I hope this information is of help to you and your patient.
All my best.
Dennis K. Ledford, MD, FAAAAI