Sandalwood paste applied externally has been reported to cause skin irritation on rare occasions. There is also one case report of a man developing a skin rash after burning large quantities of sandalwood incense.
– Blumenthal M, ed. The Complete German Commission E Monographs, Therapeutic Guide to Herbal Medicines. Austin, TX: American Botanical Council; Boston, MA: Integrative Medicine Communications; 1998: 118. — Sandra A, Shenoi SD, Srinivas CR. Allergic contact dermatitis from red sandalwood (Pterocarpus santalinus). Contact Dermatitis. 1996;34:69. — Sharma R, Bajaj AK, Singh KG. Sandalwood dermatitis. Int J Dermatol. 1987;26:597.

The perfume in the incense was volatized in air when incense was burnt; skin surface contact occurred with airborne particle, which dissolved in sebum; thus allergic contact dermatitis accompanied by depigmentation might arise.
– Contact Dermatitis 1987 May;16(5):272-4 — Depigmented contact dermatitis due to incense. — Hayakawa R, Matsunaga K, Arima Y.

Allergies to sandalwood and possible contact dermatitis.
– Am J Contact Dermat 1996 Jun;7(2):77-83 — Fragrance contact dermatitis: a worldwide multicenter investigation (Part I). — Larsen W, Nakayama H, Lindberg M, Fischer T, Elsner P, Burrows D, Jordan W, Shaw S, Wilkinson J, Marks J Jr, Sugawara M, Nethercott J.

Not recommended for use by children and pregnant or nursing women.