Topical niacinamide 4% and desonide 0.05% for treatment of axillary hyperpigmentation: a randomized, double-blind, placebo-controlled study

Figures & data

Table 1 Clinical features of the 24 female patients at baseline

Age (years), mean (SD)	21.7 ± 1.6
Skin phototype, n (%)
III	5 (21)
IV	11 (46)
V	8 (33)
Duration of AHP (years)
Mean (SD)	5.8 ± 1.7
Body mass index
Mean (SD)	23.5 ± 2.5
Hair removal methods, n (%)
Axillary shaving	87% (21)
Waxing	8% (2)
Plucking	4% (1)
Daily hygiene habits, n (%)
Antiperspirant use	24 (100)
Cleansing	24 (100)
Axillary colorimetry, mean (SD)
L*	51.2 ± 5.3
a*	9.1 ± 1.2

Abbreviations: AHP, axillary hyperpigmentation; SD, standard deviation.

Figure 1 Effect of niacinamide (n = 16), desonide (n = 16), and placebo (n = 16) on the luminosity change (L*Δ) in axillae treated during the study.

Notes: The bar chart shows differences between the group means during the study. *P ≤ 0.05, statistically significant compared with placebo. Both drugs were better than placebo at 9 weeks, but desonide improved the axillary hyperpigmentation better than niacinamide (t-test, P = 0.002).

Figure 2 Physician assessment of improvement in axillary hyperpigmentation at the end of treatment (week 9).

Notes: The efficacy of niacinamide and desonide was rated equally for good and excellent response (P = 0.5, and P = 0.8, χ² test). The placebo response was significantly lower compared with both drugs for these categories (P < 0.001, χ² test).

Figure 3 Photographs showing an excellent clinical response to treatment. (A) Axillae in a 22-year-old woman treated with niacinamide (left image). (B) The desonide-treated side in a 25-year-old woman at baseline and after 9 weeks of therapy (right image).

Figure 4 Reduction of epidermal melanin content (Fontana-Masson staining, 400×) after niacinamide and desonide, compared with placebo (first row).

Notes: Shown in the second row are representative examples of skin tissues stained with hematoxylin and eosin (200×) where numbers of mononuclear cells are more abundant in the placebo group. Immunohistochemical staining of skin tissues for CD68 cells (100×) and collagen type IV (400×) in the third and fourth row showing a reduction of CD68 expression and increased basal membrane continuity for niacinamide and desonide compared with placebo. Collagen IV interruption sites and CD68 cells are pointed out with arrowheads. Bars show approximate measures.
Abbreviations: HE, hematoxylin and eosin staining; FM, Fontana-Masson staining.

Table 2 Changes in colorimetric values (L*Δ, a*Δ), melanin content, mononuclear cells, NKI/Beteb, CD1a, CD68, collagen IV expression, and epidermal thickness in axillae treated with niacinamide, desonide, and placebo

	Niacinamide			Desonide			Placebo
	Baseline	9 weeks	P	Baseline	9 weeks	P	Baseline	9 weeks	P
L*Δ	11.8 ± 5.1	8.9 ± 4.6	<0.001	10.4 ± 4.2	6.2 ± 5.6	<0.001	11 ± 4.7	11.1 ± 4.6	0.9
a*Δ	1.3 ± 2	0.8 ± 2.1	0.1	1.2 ± 1.9	0.5 ± 1.8	0.003	1.4 ± 2.2	1.1 ± 1.9	0.7
Melanin	14.1 ± 8.5	4.9 ± 2.2	<0.001	14.5 ± 8.7	4.7 ± 2.7	<0.001	15.5 ± 8.7	14.2 ± 7.4	0.6
NKI/Beteb	23.1 ± 5.9	26.2 ± 4.3	0.1	24.3 ± 6.4	27.2 ± 1.8	0.1	26.5 ± 6.2	23.1 ± 7.5	0.1
Mononuclear cells	1585 ± 603	1184 ± 417	0.03	1474 ± 589	1044 ± 281	0.01	1630 ± 601	1543 ± 532	0.6
CD1a	35.6 ± 10.4	27.1 ± 10.2	0.9	29.6 ± 12.1	29.1 ± 14.6	0.1	30.3 ± 11.8	28.3 ± 13.6	0.7
CD68	6.4 ± 2	4.4 ± 3.2	0.05	6 ± 1.9	4.2 ± 2.5	0.03	5.9 ± 1.8	5.2 ± 2.7	0.4
Collagen IV	39 ± 21	24.4 ± 14.4	0.02	39.7 ± 21.6	20.1 ± 14.5	0.005	38.5 ± 18.5	30.1 ± 17.2	0.1
Epidermal thickness	75.4 ± 37.8	73.3 ± 38.1	0.8	68.1 ± 36.7	75.3 ± 38	0.5	69.7 ± 32.7	76.9 ± 35.1	0.5

Note: Data are shown for each intervention at baseline and at the end of the study. Data are expressed as the mean ± standard deviation. Melanin (Fontana-Masson staining) represents the fraction (%) stained per mm² of epidermis. Inflammatory cells and positive for CD1, CD68, and NKI/Beteb antibodies were estimated in counts/mm² for the whole specimen. Collagen IV was measured as a relative percentage of disruption. Epidermal thickness is in μm.

Figure 5 (A) Relationship between values in luminosity differences (L*Δ) of the affected axillae, and the percent of basal membrane discontinuity expressed as collagen IV staining for the interventions at the end of the study. A significant association was only evident for desonide (P = 0.01). (B) Relationship between melanin content by Fontana-Masson staining and collagen IV expression for each intervention at the conclusion of the study.

Note: The association was significant for desonide and placebo (P = 0.04, for both).