Triamcinolone acetonide is most often used. It can be diluted with normal saline or lignocaine and is delivered in volumes of 1-2 mL. The concentration used depends on the pathology and skin site. Generally, one commences with a concentration of 5 mg/mL working up to the full concentration of 40 mg/mL, if necessary, when there is no response. If required, the injection can be repeated every 4-6 weeks. The adverse effects include pain, secondary infection, telangiectasia, leucoderma and dermal atrophy. Systemic adverse effects are rare unless large quantities are used. Intralesional steroids are not used for epidermal conditions. Care is required to introduce the steroid deep into the dermis to avoid epidermal atrophy, as well as dermal atrophy in those conditions where there is not a grossly thickened dermis. In the case of keloid, atrophy of the dermis following the use of treatment is unlikely to be a problem.
The inhaler device efficiency is expected to influence inhaled corticosteroid therapeutic dose equivalence. Device efficiency (lung deposited dose/nominal dose) varies for dry-powder (DPI) and metered-dose (MDI) inhalers. The largest differences are seen between DPIs and chlorofluorocarbon (CFC) MDIs of low- to mid-range efficiency that emit particles mostly in the 3–5 µm range when compared with MDIs that contain drug dissolved in hydrofluoroalkane (HFA) propellant and generate an ultrafine aerosol plume with smaller particles (≈1 µm) and a greater proportion of the particles in the respirable range (<5 µm) [ 16 ]. The impact of device efficiency on therapeutic dose is explored in Figure 3 , which has on the y-axis the total daily dose estimated to be deposited in the lungs, obtained by correcting the nominal dose for the device efficiency. Figure 3 also includes data for DPIs and MDIs of both the CFC and higher-efficiency ultrafine aerosol HFA MDIs (FLU, BDP, CIC) (Table 1 ). Also included are low-, mid- and high-dose regimens of all currently available inhaled corticosteroids, illustrating for each dose level a distinct exponential decline in therapeutic daily dose with increasing potency. Therefore, one might expect that all dose regimens in the low-, mid- or high-dose categories, as defined by each regression line, should have equivalent efficacy. This may be the case, but is difficult to verify as the extent to which each product's recommended doses are based on comprehensive dose ranging in all severities of asthma is variable.