Table I.

Characteristics of Patients taking antihistamines (n=7).

Patient Number	name of antihistamine used	nights on antihistamine	nights off antihistamine	mean WASO on antihistamine	mean WASO off antihistamine	P-value*	mean Sleep onset Latency on antihistamine	mean Sleep onset Latency off antihistamine	P-value*
Patient1	cetirizine	1	5	129.5	154.4	0.80	0.0	52.6	0.14
Patient2	diphenhydramine	2	3	66.0	106.7	0.08	28.0	45.2	0.25
Patient3	cetrizine	2	5	158.5	106.2	0.44	22.5	2.4	0.03
Patient4	hydroxyzine	7	0	154.9			1.8
Patient5	hydroxyzine	1	6	74.5	67.6	0.78	5.0	2.6	0.27
Patient6	hydroxyzine	7	0	295.7			0††
Patient7	one night levocetirizine, other nights hydroxyzine	4	3	86.1	95.0	0.48	1.8	3.2	0.59

^*Mann-Whitney U test

^††Severely fragmented sleep and sleep onset latency was computed as 0 minutes for all nights

Patients on antihistamines trended towards having more severe disease (SCORAD µ=70.4±19.7 (n=7 subjects) v. 50.7±20.3 (n=12), p=0.06). Sleep onset latency trended to be shorter on antihistamine versus non-antihistamine nights (µ=5.2±3.8 minutes (n=24 nights) v. 15.6±1.9 (n=97), p=0.07). Minutes of Wake After Sleep Onset (WASO) were higher on the nights of antihistamine use (µ=173.0±11.1 minutes (n=24 nights) v. 88.2±5.5 (n=97), p<0.01); it is possible that antihistamines were used intermittently because of increased AD severity.